Sound source localization and segregation with internally coupled ears

DEFF Research Database (Denmark)

Bee, Mark A; Christensen-Dalsgaard, Jakob

2016-01-01

to their correct sources (sound source segregation). Here, we review anatomical, biophysical, neurophysiological, and behavioral studies aimed at identifying how the internally coupled ears of frogs contribute to sound source localization and segregation. Our review focuses on treefrogs in the genus Hyla......, as they are the most thoroughly studied frogs in terms of sound source localization and segregation. They also represent promising model systems for future work aimed at understanding better how internally coupled ears contribute to sound source localization and segregation. We conclude our review by enumerating...

Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

Science.gov (United States)

Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

2016-01-01

A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates over the evanescent sound field because of broadening of the wavenumber spectrum. Therefore, we calculated the optimum distribution of the particle velocity on the vibrating plate to reduce the broadening of the wavenumber spectrum. We focused on a window function that is utilized in the field of signal analysis for reducing the broadening of the frequency spectrum. The optimization calculation is necessary for the design of window function suitable for suppressing sound radiation and securing a spatial area for data communication. In addition, a wide frequency bandwidth is required to increase the data transmission speed. Therefore, we investigated a suitable method for calculating the sound pressure level at the far field to confirm the variation of the distribution of sound pressure level determined on the basis of the window shape and frequency. The distribution of the sound pressure level at a finite distance was in good agreement with that obtained at an infinite far field under the condition generating the evanescent sound field. Consequently, the window function was optimized by the method used to calculate the distribution of the sound pressure level at an infinite far field using the wavenumber spectrum on the vibrating plate. According to the result of comparing the distributions of the sound pressure level in the cases with and without the window function, it was confirmed that the area whose sound pressure level was reduced from the maximum level to -50 dB was

Sound reduction by metamaterial-based acoustic enclosure

Directory of Open Access Journals (Sweden)

Shanshan Yao

2014-12-01

Full Text Available In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of the source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.

Sound reduction by metamaterial-based acoustic enclosure

Energy Technology Data Exchange (ETDEWEB)

Yao, Shanshan; Li, Pei; Zhou, Xiaoming; Hu, Gengkai, E-mail: hugeng@bit.edu.cn [Key Laboratory of Dynamics and Control of Flight Vehicle, Ministry of Education and School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2014-12-15

In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of the source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.

The baffle influence on sound radiation characteristics of a plate

Directory of Open Access Journals (Sweden)

Bao Liu

2017-01-01

Full Text Available The acoustic radiation characteristics of the baffle plates and unbaffle plates are calculated and compared by single-layer potential and double-layer potential. Based on the boundary integral equation, the sound pressure integral equation of the baffle and the baffle are deduced respectively. According to the boundary compatibility condition, the sound pressure and the vibration velocity of the plates are obtained. Further, the dynamic equation of the structure is substituted into the vibration equation in the form of the baffle plate and the baffle plate. The sound pressure difference and the displacement of a plate surface are in the form of the vibration mode superposition and the acoustic radiation impedance of the double integral form is obtained, which determines vibration mode coefficient and sound radiation parameters. The effect of the baffle on the acoustic radiation characteristics of the thin plate is analyzed by comparing the acoustic radiation parameters with the simple and simple rectangular plate in water.

Frequency-independent radiation modes of interior sound radiation: Experimental study and global active control

Science.gov (United States)

Hesse, C.; Papantoni, V.; Algermissen, S.; Monner, H. P.

2017-08-01

Active control of structural sound radiation is a promising technique to overcome the poor passive acoustic isolation performance of lightweight structures in the low-frequency region. Active structural acoustic control commonly aims at the suppression of the far-field radiated sound power. This paper is concerned with the active control of sound radiation into acoustic enclosures. Experimental results of a coupled rectangular plate-fluid system under stochastic excitation are presented. The amplitudes of the frequency-independent interior radiation modes are determined in real-time using a set of structural vibration sensors, for the purpose of estimating their contribution to the acoustic potential energy in the enclosure. This approach is validated by acoustic measurements inside the cavity. Utilizing a feedback control approach, a broadband reduction of the global acoustic response inside the enclosure is achieved.

Method for measuring violin sound radiation based on bowed glissandi and its application to sound synthesis.

Science.gov (United States)

Perez Carrillo, Alfonso; Bonada, Jordi; Patynen, Jukka; Valimaki, Vesa

2011-08-01

This work presents a method for measuring and computing violin-body directional frequency responses, which are used for violin sound synthesis. The approach is based on a frame-weighted deconvolution of excitation and response signals. The excitation, consisting of bowed glissandi, is measured with piezoelectric transducers built into the bridge. Radiation responses are recorded in an anechoic chamber with multiple microphones placed at different angles around the violin. The proposed deconvolution algorithm computes impulse responses that, when convolved with any source signal (captured with the same transducer), produce a highly realistic violin sound very similar to that of a microphone recording. The use of motion sensors allows for tracking violin movements. Combining this information with the directional responses and using a dynamic convolution algorithm, helps to improve the listening experience by incorporating the violinist motion effect in stereo.

Active control of radiated sound power from a baffled, rectangular panel

DEFF Research Database (Denmark)

Mørkholt, Jakob

1996-01-01

with an array of eleven microphones in front of the panel, is very close to minimising the actual radiated sound power. Practical experiments where such an array estimate has been minimised using the filtered X LMS algorithm have shown that substantial reductions of radiated sound power can be obtained over......Active control of radiated sound power from a rectangular baffled panel by minimisation of an accurate power estimate, using piezoceramic actuators, has been investigated. Computer simulations have shown that minimising a power estimate obtained by discretised integration of the far field intensity...... a broad frequency range using few piezoceramic actuators, provided that an accurate estimate of the sound power is available for minimisation....

Sound Radiation of Aerodynamically Excited Flat Plates into Cavities

Directory of Open Access Journals (Sweden)

Johannes Osterziel

2017-10-01

Full Text Available Flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate are experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters are determined through measurements with a hot-wire anemometer in an aeroacoustic wind tunnel. Furthermore, the excitation of the vibrating plate is examined by laser scanning vibrometry. To describe the sound radiation and the sound transmission of the flexible aluminium plates into cavities, a cuboid-shaped room with adjustable volume and 34 flush-mounted microphones is installed at the non flow-excited side of the aluminium plates. Results showed that the sound field inside the cavity is on the one hand dependent on the flow parameters and the plate thickness and on the other hand on the cavity volume which indirectly influences the level and the distribution of the sound pressure behind the flexible plate through different excited modes.

Sound radiation modes of cylindrical surfaces and their application to vibro-acoustics analysis of cylindrical shells

Science.gov (United States)

Sun, Yao; Yang, Tiejun; Chen, Yuehua

2018-06-01

In this paper, sound radiation modes of baffled cylinders have been derived by constructing the radiation resistance matrix analytically. By examining the characteristics of sound radiation modes, it is found that radiation coefficient of each radiation mode increases gradually with the increase of frequency while modal shapes of sound radiation modes of cylindrical shells show a weak dependence upon frequency. Based on understandings on sound radiation modes, vibro-acoustics behaviors of cylindrical shells have been analyzed. The vibration responses of cylindrical shells are described by modified Fourier series expansions and solved by Rayleigh-Ritz method involving Flügge shell theory. Then radiation efficiency of a resonance has been determined by examining whether the vibration pattern is in correspondence with a sound radiation mode possessing great radiation efficiency. Furthermore, effects of thickness and boundary conditions on sound radiation of cylindrical shells have been investigated. It is found that radiation efficiency of thicker shells is greater than thinner shells while shells with a clamped boundary constraint radiate sound more efficiently than simply supported shells under thin shell assumption.

Material sound source localization through headphones

Science.gov (United States)

Dunai, Larisa; Peris-Fajarnes, Guillermo; Lengua, Ismael Lengua; Montaña, Ignacio Tortajada

2012-09-01

In the present paper a study of sound localization is carried out, considering two different sounds emitted from different hit materials (wood and bongo) as well as a Delta sound. The motivation of this research is to study how humans localize sounds coming from different materials, with the purpose of a future implementation of the acoustic sounds with better localization features in navigation aid systems or training audio-games suited for blind people. Wood and bongo sounds are recorded after hitting two objects made of these materials. Afterwards, they are analysed and processed. On the other hand, the Delta sound (click) is generated by using the Adobe Audition software, considering a frequency of 44.1 kHz. All sounds are analysed and convolved with previously measured non-individual Head-Related Transfer Functions both for an anechoic environment and for an environment with reverberation. The First Choice method is used in this experiment. Subjects are asked to localize the source position of the sound listened through the headphones, by using a graphic user interface. The analyses of the recorded data reveal that no significant differences are obtained either when considering the nature of the sounds (wood, bongo, Delta) or their environmental context (with or without reverberation). The localization accuracies for the anechoic sounds are: wood 90.19%, bongo 92.96% and Delta sound 89.59%, whereas for the sounds with reverberation the results are: wood 90.59%, bongo 92.63% and Delta sound 90.91%. According to these data, we can conclude that even when considering the reverberation effect, the localization accuracy does not significantly increase.

A particle velocity based method for separating all multi incoherent sound sources

NARCIS (Netherlands)

Winkel, J.C.; Yntema, Doekle Reinder; Druyvesteyn, W.F.; de Bree, H.E.

2006-01-01

In this paper we present a method to separate the contributions of different uncorrelated sound sources to the total sound field. When the contribution of each sound source to the total sound field is known, techniques with array-applications like direct sound field measurements or inverse acoustics

Binaural Processing of Multiple Sound Sources

Science.gov (United States)

2016-08-18

AFRL-AFOSR-VA-TR-2016-0298 Binaural Processing of Multiple Sound Sources William Yost ARIZONA STATE UNIVERSITY 660 S MILL AVE STE 312 TEMPE, AZ 85281...18-08-2016 2. REPORT TYPE Final Performance 3. DATES COVERED (From - To) 15 Jul 2012 to 14 Jul 2016 4. TITLE AND SUBTITLE Binaural Processing of...three topics cited above are entirely within the scope of the AFOSR grant. 15. SUBJECT TERMS Binaural hearing, Sound Localization, Interaural signal

Task-Modulated Cortical Representations of Natural Sound Source Categories

DEFF Research Database (Denmark)

Hjortkjær, Jens; Kassuba, Tanja; Madsen, Kristoffer Hougaard

2018-01-01

In everyday sound environments, we recognize sound sources and events by attending to relevant aspects of an acoustic input. Evidence about the cortical mechanisms involved in extracting relevant category information from natural sounds is, however, limited to speech. Here, we used functional MRI...

Offshore dredger sounds: Source levels, sound maps, and risk assessment

NARCIS (Netherlands)

Jong, C.A.F. de; Ainslie, M.A.; Heinis, F.; Janmaat, J.

2016-01-01

The underwater sound produced during construction of the Port of Rotterdam harbor extension (Maasvlakte 2) was measured, with emphasis on the contribution of the trailing suction hopper dredgers during their various activities: dredging, transport, and discharge of sediment. Measured source levels

Vibration analysis and sound field characteristics of a tubular ultrasonic radiator.

Science.gov (United States)

Liang, Zhaofeng; Zhou, Guangping; Zhang, Yihui; Li, Zhengzhong; Lin, Shuyu

2006-12-01

A sort of tubular ultrasonic radiator used in ultrasonic liquid processing is studied. The frequency equation of the tubular radiator is derived, and its radiated sound field in cylindrical reactor is calculated using finite element method and recorded by means of aluminum foil erosion. The results indicate that sound field of tubular ultrasonic radiator in cylindrical reactor appears standing waves along both its radial direction and axial direction, and amplitudes of standing waves decrease gradually along its radial direction, and the numbers of standing waves along its axial direction are equal to the axial wave numbers of tubular radiator. The experimental results are in good agreement with calculated results.

Noise source separation of diesel engine by combining binaural sound localization method and blind source separation method

Science.gov (United States)

Yao, Jiachi; Xiang, Yang; Qian, Sichong; Li, Shengyang; Wu, Shaowei

2017-11-01

In order to separate and identify the combustion noise and the piston slap noise of a diesel engine, a noise source separation and identification method that combines a binaural sound localization method and blind source separation method is proposed. During a diesel engine noise and vibration test, because a diesel engine has many complex noise sources, a lead covering method was carried out on a diesel engine to isolate other interference noise from the No. 1-5 cylinders. Only the No. 6 cylinder parts were left bare. Two microphones that simulated the human ears were utilized to measure the radiated noise signals 1 m away from the diesel engine. First, a binaural sound localization method was adopted to separate the noise sources that are in different places. Then, for noise sources that are in the same place, a blind source separation method is utilized to further separate and identify the noise sources. Finally, a coherence function method, continuous wavelet time-frequency analysis method, and prior knowledge of the diesel engine are combined to further identify the separation results. The results show that the proposed method can effectively separate and identify the combustion noise and the piston slap noise of a diesel engine. The frequency of the combustion noise and the piston slap noise are respectively concentrated at 4350 Hz and 1988 Hz. Compared with the blind source separation method, the proposed method has superior separation and identification effects, and the separation results have fewer interference components from other noise.

Sound quality prediction for engine-radiated noise

Science.gov (United States)

Liu, Hai; Zhang, Junhong; Guo, Peng; Bi, Fengrong; Yu, Hanzhengnan; Ni, Guangjian

2015-05-01

Diesel engine-radiated noise quality prediction is an important topic because engine noise has a significant impact on the overall vehicle noise. Sound quality prediction is based on subjective and objective evaluation of engine noise. The integrated satisfaction index (ISI) is proposed as a criterion for differentiate noise quality in the subjective evaluation, and five psychoacoustic parameters are selected for characterizing and analyzing the noise quality of the diesel engine objectively. The combination of support vector machines (SVM) and genetic algorithm (GA) is proposed in order to establish a model for predicting the diesel engine-radiated noise quality for all operation conditions. The performance of the GA-SVM model is compared with the BP neural network model, and the results show that the mean relative error of the GA-SVM model is smaller than the BP neural network model. The importance rank of the sound quality metrics to the ISI is indicated by the non-parametric correlation analysis. This study suggests that the GA-SVM model is very useful for accurately predicting the diesel engine-radiated noise quality.

The natural horn as an efficient sound radiating system ...

African Journals Online (AJOL)

Results obtained showed that the locally made horn are efficient sound radiating systems and are therefore excellent for sound production in local musical renditions. These findings, in addition to the portability and low cost of the horns qualify them to be highly recommended for use in music making and for other purposes ...

Orientation Estimation and Signal Reconstruction of a Directional Sound Source

DEFF Research Database (Denmark)

Guarato, Francesco

, one for each call emission, were compared to those calculated through a pre-existing technique based on interpolation of sound-pressure levels at microphone locations. The application of the method to the bat calls could provide knowledge on bat behaviour that may be useful for a bat-inspired sensor......Previous works in the literature about one tone or broadband sound sources mainly deal with algorithms and methods developed in order to localize the source and, occasionally, estimate the source bearing angle (with respect to a global reference frame). The problem setting assumes, in these cases......, omnidirectional receivers collecting the acoustic signal from the source: analysis of arrival times in the recordings together with microphone positions and source directivity cues allows to get information about source position and bearing. Moreover, sound sources have been included into sensor systems together...

Spatial resolution limits for the localization of noise sources using direct sound mapping

DEFF Research Database (Denmark)

Comesana, D. Fernandez; Holland, K. R.; Fernandez Grande, Efren

2016-01-01

the relationship between spatial resolution, noise level and geometry. The proposed expressions are validated via simulations and experiments. It is shown that particle velocity mapping yields better results for identifying closely spaced sound sources than sound pressure or sound intensity, especially...... extensively been used for many years to locate sound sources. However, it is not yet well defined when two sources should be regarded as resolved by means of direct sound mapping. This paper derives the limits of the direct representation of sound pressure, particle velocity and sound intensity by exploring......One of the main challenges arising from noise and vibration problems is how to identify the areas of a device, machine or structure that produce significant acoustic excitation, i.e. the localization of main noise sources. The direct visualization of sound, in particular sound intensity, has...

Active structural acoustic control for reduction of radiated sound from structure

International Nuclear Information System (INIS)

Hong, Jin Seok; Oh, Jae Eung

2001-01-01

Active control of sound radiation from a vibrating rectangular plate by a steady-state harmonic point force disturbance is experimentally studied. Structural excitation is achieved by two piezoceramic actuators mounted on the panel. Two accelerometers are implemented as error sensors. Estimated radiated sound signals using vibro-acoustic path transfer function are used as error signals. The vibro-acoustic path transfer function represents system between accelerometers and microphones. The approach is based on a multi-channel filtered-x LMS algorithm. The results shows that attenuation of sound levels of 11dB, 10dB is achieved

Reconstruction of Sound Source Pressures in an Enclosure Using the Phased Beam Tracing Method

DEFF Research Database (Denmark)

Jeong, Cheol-Ho; Ih, Jeong-Guon

2009-01-01

. First, surfaces of an extended source are divided into reasonably small segments. From each source segment, one beam is projected into the field and all emitted beams are traced. Radiated beams from the source reach array sensors after traveling various paths including the wall reflections. Collecting...... all the pressure histories at the field points, source-observer relations can be constructed in a matrix-vector form for each frequency. By multiplying the measured field data with the pseudo-inverse of the calculated transfer function, one obtains the distribution of source pressure. An omni......-directional sphere and a cubic source in a rectangular enclosure were taken as examples in the simulation tests. A reconstruction error was investigated by Monte Carlo simulation in terms of field point locations. When the source information was reconstructed by the present method, it was shown that the sound power...

Offshore dredger sound: source levels, sound maps and risk assessment (abstract)

NARCIS (Netherlands)

Jong, C.A.F. de; Ainslie, M.A.; Heinis, F.; Janmaat, J.

2013-01-01

The Port of Rotterdam is expanding to meet the growing demand to accommodate large cargo vessels. One of the licensing conditions was the monitoring of the underwater sound produced during its construction, with an emphasis on the establishment of acoustic source levels of the Trailing Suction

A method for estimating the orientation of a directional sound source from source directivity and multi-microphone recordings: principles and application

DEFF Research Database (Denmark)

Guarato, Francesco; Jakobsen, Lasse; Vanderelst, Dieter

2011-01-01

Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in the ultra......Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in...

Measurement of energetic radiation caused by thunderstorm activities by a sounding balloon and ground observation

Science.gov (United States)

Torii, T.

2015-12-01

Energetic radiation caused by thunderstorm activity is observed at various places, such as the ground, high mountain areas, and artificial satellites. In order to investigate the radiation source and its energy distribution, we measured energetic radiation by a sounding balloon, and the ground observation. On the measurement inside/above the thundercloud, we conducted a sounding observation using a radiosonde mounted two GM tubes (for gamma-rays, and for beta/gamma-rays), in addition to meteorological instruments. The balloon passed through a region of strong echoes in a thundercloud shown by radar image, at which time an increase in counting rate of the GM tube about 2 orders of magnitude occurred at the altitude from 5 km to 7.5 km. Furthermore, the counting rate of two GM tubes indicated the tendency different depending on movement of a balloon. This result suggests that the ratio for the gamma-rays (energetic photons) of the beta-rays (energetic electrons) varies according to the place in the thundercloud. Furthermore, we carried out a ground observation of the energetic gamma rays during winter thunderstorm at a coastal area facing the Sea of Japan. Two types of the energetic radiation have been observed at this time. We report the outline of these measurements and analysis in the session of the AGU meeting.

Sound field separation with sound pressure and particle velocity measurements

DEFF Research Database (Denmark)

Fernandez Grande, Efren; Jacobsen, Finn; Leclère, Quentin

2012-01-01

separation techniques make it possible to distinguish between outgoing and incoming waves from the two sides, and thus NAH can be applied. In this paper, a separation method based on the measurement of the particle velocity in two layers and another method based on the measurement of the pressure...... and the velocity in a single layer are proposed. The two methods use an equivalent source formulation with separate transfer matrices for the outgoing and incoming waves, so that the sound from the two sides of the array can be modeled independently. A weighting scheme is proposed to account for the distance......In conventional near-field acoustic holography (NAH) it is not possible to distinguish between sound from the two sides of the array, thus, it is a requirement that all the sources are confined to only one side and radiate into a free field. When this requirement cannot be fulfilled, sound field...

Reproduction of nearby sound sources using higher-order ambisonics with practical loudspeaker arrays

DEFF Research Database (Denmark)

Favrot, Sylvain Emmanuel; Buchholz, Jörg

2012-01-01

the impact of two existing and a new proposed regularization function on the reproduced sound fields and on the main auditory cue for nearby sound sources outside the median plane, i.e, low-frequencies interaural level differences (ILDs). The proposed regularization function led to a better reproduction......In order to reproduce nearby sound sources with distant loudspeakers to a single listener, the near field compensated (NFC) method for higher-order Ambisonics (HOA) has been previously proposed. In practical realization, this method requires the use of regularization functions. This study analyzes...... of point source sound fields compared to existing regularization functions for NFC-HOA. Measurements in realistic playback environments showed that, for very close sources, significant ILDs for frequencies above about 250 Hz can be reproduced with NFC-HOA and the proposed regularization function whereas...

Ionizing radiation, radiation sources, radiation exposure, radiation effects. Pt. 2

International Nuclear Information System (INIS)

Schultz, E.

1985-01-01

Part 2 deals with radiation exposure due to artificial radiation sources. The article describes X-ray diagnosis complete with an analysis of major methods, nuclear-medical diagnosis, percutaneous radiation therapy, isotope therapy, radiation from industrial generation of nucler energy and other sources of ionizing radiation. In conclusion, the authors attempt to asses total dose, genetically significant dose and various hazards of total radiation exposure by means of a summation of all radiation impacts. (orig./WU) [de

The status of safety of radiation sources and security of radioactive materials in Ethiopia

International Nuclear Information System (INIS)

Gebeyehu Wolde, G.

2001-01-01

Since 1993, the National Radiation Protection Authority (NRPA) has been empowered by the 'Radiation Protection Proclamation no. 79/1993' to authorize and inspect regulated activities, issue guidelines and standards and enforce the legislation and regulations. The report describes the status of the safety of radiation sources and the security of radioactive materials in Ethiopia and the progress made towards building a sound and effective national regulatory infrastructure. Also, the report highlights the challenges and difficulties encountered and concludes by indicating the way forward towards the strategic goals. (author)

High frequency ion sound waves associated with Langmuir waves in type III radio burst source regions

Directory of Open Access Journals (Sweden)

G. Thejappa

2004-01-01

Full Text Available Short wavelength ion sound waves (2-4kHz are detected in association with the Langmuir waves (~15-30kHz in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir waves occur as coherent field structures with peak intensities exceeding the Langmuir collapse thresholds. Their scale sizes are of the order of the wavelength of an ion sound wave. These Langmuir wave field characteristics indicate that the observed short wavelength ion sound waves are most probably generated during the thermalization of the burnt-out cavitons left behind by the Langmuir collapse. Moreover, the peak intensities of the observed short wavelength ion sound waves are comparable to the expected intensities of those ion sound waves radiated by the burnt-out cavitons. However, the speeds of the electron beams derived from the frequency drift of type III radio bursts are too slow to satisfy the needed adiabatic ion approximation. Therefore, some non-linear process such as the induced scattering on thermal ions most probably pumps the beam excited Langmuir waves towards the lower wavenumbers, where the adiabatic ion approximation is justified.

Reconstruction of sound source signal by analytical passive TR in the environment with airflow

Science.gov (United States)

Wei, Long; Li, Min; Yang, Debin; Niu, Feng; Zeng, Wu

2017-03-01

In the acoustic design of air vehicles, the time-domain signals of noise sources on the surface of air vehicles can serve as data support to reveal the noise source generation mechanism, analyze acoustic fatigue, and take measures for noise insulation and reduction. To rapidly reconstruct the time-domain sound source signals in an environment with flow, a method combining the analytical passive time reversal mirror (AP-TR) with a shear flow correction is proposed. In this method, the negative influence of flow on sound wave propagation is suppressed by the shear flow correction, obtaining the corrected acoustic propagation time delay and path. Those corrected time delay and path together with the microphone array signals are then submitted to the AP-TR, reconstructing more accurate sound source signals in the environment with airflow. As an analytical method, AP-TR offers a supplementary way in 3D space to reconstruct the signal of sound source in the environment with airflow instead of the numerical TR. Experiments on the reconstruction of the sound source signals of a pair of loud speakers are conducted in an anechoic wind tunnel with subsonic airflow to validate the effectiveness and priorities of the proposed method. Moreover the comparison by theorem and experiment result between the AP-TR and the time-domain beamforming in reconstructing the sound source signal is also discussed.

Perceived loudness of spatially distributed sound sources

DEFF Research Database (Denmark)

Song, Woo-keun; Ellermeier, Wolfgang; Minnaar, Pauli

2005-01-01

psychoacoustic attributes into account. Therefore, a method for deriving loudness maps was developed in an earlier study [Song, Internoise2004, paper 271]. The present experiment investigates to which extent perceived loudness depends on the distribution of individual sound sources. Three loudspeakers were...... positioned 1.5 m from the centre of the listener’s head, one straight ahead, and two 10 degrees to the right and left, respectively. Six participants matched the loudness of either one, or two simultaneous sounds (narrow-band noises with 1-kHz, and 3.15-kHz centre frequencies) to a 2-kHz, 60-dB SPL narrow......-band noise placed in the frontal loudspeaker. The two sounds were either originating from the central speaker, or from the two offset loudspeakers. It turned out that the subjects perceived the noises to be softer when they were distributed in space. In addition, loudness was calculated from the recordings...

Sensitivity to plant modelling uncertainties in optimal feedback control of sound radiation from a panel

DEFF Research Database (Denmark)

Mørkholt, Jakob

1997-01-01

Optimal feedback control of broadband sound radiation from a rectangular baffled panel has been investigated through computer simulations. Special emphasis has been put on the sensitivity of the optimal feedback control to uncertainties in the modelling of the system under control.A model...... in terms of a set of radiation filters modelling the radiation dynamics.Linear quadratic feedback control applied to the panel in order to minimise the radiated sound power has then been simulated. The sensitivity of the model based controller to modelling uncertainties when using feedback from actual...

On-axis and far-field sound radiation from resilient flat and dome-shaped radiators

NARCIS (Netherlands)

Aarts, R.M.; Janssen, A.J.E.M.

2009-01-01

On-axis and far-field series expansions are developed for the sound pressure due to an arbitrary, circular symmetric velocity distribution on a flat radiator in an infinite baffle. These expansions are obtained by expanding the velocity distributions in terms of orthogonal polynomials

The Environmental Cost of Marine Sound Sources

NARCIS (Netherlands)

Ainslie, M.A.; Dekeling, R.P.A.

2011-01-01

Cumulative acoustic exposure is used as an indicator for the risk of negative impact to animals as a consequence of exposure to underwater sound. The free-field energy of a single source, defined as the total acoustic energy that would exist in the source’s free field, is shown to be closely related

Stabilized platform for tethered balloon soundings of broadband long- and short-wave radiation

International Nuclear Information System (INIS)

Alzheimer, J.M.; Anderson, G.A.; Whiteman, C.D.

1993-01-01

Changes in the composition of trace gases in the earth's atmosphere have been reported by many observers, and a general concern has been expressed regarding possible changes to the earth's climate that may be caused by radiatively active gases introduced into the earth's atmosphere by man's activities. Radiatively active trace gases produce temperature changes in the earth's atmosphere through changes in radiative flux divergence. Our knowledge of and means of measuring radiative flux divergence is very limited. A few observations of vertical radiative flux divergences have been reported from aircraft from radiometersondes from towers and from large tethered balloons. These measurement techniques suffers from one or more drawbacks, including shallow sounding depths (towers), high cost (aircraft), complicated logistics (large tethered balloons), and limitation to nighttime hours (radiometersondes). Changes in radiative flux divergence caused by anthropogenic trace gases are expected to be quite small, and will be difficult to measure with existing broadband radiative flux instruments. The emphasis of present research in global climate change is thus being focused on improving radiative transfer algorithms in global climate models. The radiative parameterizations in these models are at an early stage of development and information is needed regarding their performance, especially in cloudy conditions. The impetus for the research reported in this paper is the need for a device that can supplement existing means of measuring vertical profiles of long- and short-wave irradiance and radiative flux divergence. We have designed a small tethered-balloon-based system that can make radiometric soundings through the atmospheric boundary layer. This paper discusses the concept, the design considerations, and the design and construction of this sounding system. The performance of the system will be tested in a series of balloon flights scheduled for the fall and winter of 1992

Effect of a serrated trailing edge on sound radiation from nearby quadrupoles.

Science.gov (United States)

Karimi, Mahmoud; Croaker, Paul; Kinns, Roger; Kessissoglou, Nicole

2017-05-01

A periodic boundary element technique is implemented to study the noise reduction capability of a plate with a serrated trailing edge under quadrupole excitation. It is assumed for this purpose that the quadrupole source tensor is independent of the trailing edge configuration and that the effect of the trailing edge shape is to modify sound radiation from prescribed boundary layer sources. The flat plate is modelled as a continuous structure with a finite repetition of small spanwise segments. The matrix equation formulated by the periodic boundary element method for this 3D acoustic scattering problem is represented as a block Toeplitz matrix. The discrete Fourier transform is employed in an iterative algorithm to solve the block Toeplitz system. The noise reduction mechanism for a serrated trailing edge in the near field is investigated by comparing contour plots obtained from each component of the quadrupole for unserrated and serrated trailing edge plate models. The noise reduction due to the serrated trailing edge is also examined as a function of the source location.

Converting the GSR part3 into a national regulations for the protection and safety of radiation sources

International Nuclear Information System (INIS)

Hatim, Abdulrahman

2016-04-01

The achievement and maintenance of a high level of Radiation Protection and Safety of Radiation Sources depends on a sound legal and governmental infrastructure, including a regulatory body with well-defined responsibilities and functions. The project aimed at converting the IAEA GRS Part 3 into National regulations in Sudan for the protection against the harmful effects of ionizing radiation and safety of radiation sources. The regulations developed covered general requirements for radiation protection, verification of safety, planned exposure situations, emergency exposure situations and existing exposure situation. The Government of Sudan is expected to empower the Sudanese Nuclear Radiological Regulatory Authority (SNRAA) and other relevant authorities to undertake the conversion of IAEA GSR Part 3 into national regulations to be used to regulate all facilities and activities in Sudan. (au)

Auralization of airborne sound insulation including the influence of source room

DEFF Research Database (Denmark)

Rindel, Jens Holger

2006-01-01

The paper describes a simple and acoustically accurate method for the auralization of airborne sound insulation between two rooms by means of a room acoustic simulation software (ODEON). The method makes use of a frequency independent transparency of the transmitting surface combined...... with a frequency dependent power setting of the source in the source room. The acoustic properties in terms of volume and reverberation time as well as the area of the transmitting surface are all included in the simulation. The user only has to select the position of the source in the source room and the receiver...... of the transmitting surface is used for the simulation of sound transmission. Also the reduced clarity of the auralization due to the reverberance of the source room is inherent in the method. Currently the method is restricted to transmission loss data in octave bands....

Sound Radiation from a Loudspeaker Cabinet using the Boundary Element Method

DEFF Research Database (Denmark)

Fernandez Grande, Efren

had been reported, based on subjective testing. This study aims to detect the reported problem. The radiation from the cabinet is calculated using the Boundary Element Method. The analysis examines both the frequency domain and the time domain characteristics (in other words, the steady state response......, in some cases becoming clearly audible. The aim of this study is to provide a tool that can evaluate the contribution from the cabinet to the overall sound radiated by a loudspeaker. The specific case of a B&O Beolab 9 early prototype has been investigated. An influence by the cabinet of this prototype...... and the impulse response) of the loudspeaker and the cabinet. A significant influence of the cabinet has been detected, which becomes especially apparent in the time domain, during the sound decay process....

Techniques and instrumentation for the measurement of transient sound energy flux

Science.gov (United States)

Watkinson, P. S.; Fahy, F. J.

1983-12-01

The evaluation of sound intensity distributions, and sound powers, of essentially continuous sources such as automotive engines, electric motors, production line machinery, furnaces, earth moving machinery and various types of process plants were studied. Although such systems are important sources of community disturbance and, to a lesser extent, of industrial health hazard, the most serious sources of hearing hazard in industry are machines operating on an impact principle, such as drop forges, hammers and punches. Controlled experiments to identify major noise source regions and mechanisms are difficult because it is normally impossible to install them in quiet, anechoic environments. The potential for sound intensity measurement to provide a means of overcoming these difficulties has given promising results, indicating the possibility of separation of directly radiated and reverberant sound fields. However, because of the complexity of transient sound fields, a fundamental investigation is necessary to establish the practicability of intensity field decomposition, which is basic to source characterization techniques.

Tuned sources of submillimetre radiation

International Nuclear Information System (INIS)

Berezhnyj, V.L.

1981-01-01

The main present directions of development of sources of frequency coherent tuned radiation of electromagnetic waves in the submillimeter range: nonlinear mixing of different frequencies; semiconductor lasers; molecular lasers with optical pumping; relativistic electron beams in a magnetic field as submillimeter radiation sources; submillimeter radiation sources on the basis of SHF classical electrovacuum devices - are considered. The designs of generator systems and their specifications are presented. The main parameters of electromagnetic radiation of different sources, such as: power, stability, frequency, tuning range - are presented. The methods of improving sources and electromagnetic radiation parameters are proposed. The examples of possible applications of submillimeter radiation in different spheres of science and technology are given [ru

The effect of sound sources on soundscape appraisal

NARCIS (Netherlands)

van den Bosch, Kirsten; Andringa, Tjeerd

2014-01-01

In this paper we explore how the perception of sound sources (like traffic, birds, and the presence of distant people) influences the appraisal of soundscapes (as calm, lively, chaotic, or boring). We have used 60 one-minute recordings, selected from 21 days (502 hours) in March and July 2010.

Analysis, Design and Implementation of an Embedded Realtime Sound Source Localization System Based on Beamforming Theory

Directory of Open Access Journals (Sweden)

Arko Djajadi

2009-12-01

Full Text Available This project is intended to analyze, design and implement a realtime sound source localization system by using a mobile robot as the media. The implementated system uses 2 microphones as the sensors, Arduino Duemilanove microcontroller system with ATMega328p as the microprocessor, two permanent magnet DC motors as the actuators for the mobile robot and a servo motor as the actuator to rotate the webcam directing to the location of the sound source, and a laptop/PC as the simulation and display media. In order to achieve the objective of finding the position of a specific sound source, beamforming theory is applied to the system. Once the location of the sound source is detected and determined, the choice is either the mobile robot will adjust its position according to the direction of the sound source or only webcam will rotate in the direction of the incoming sound simulating the use of this system in a video conference. The integrated system has been tested and the results show the system could localize in realtime a sound source placed randomly on a half circle area (0 - 1800 with a radius of 0.3m - 3m, assuming the system is the center point of the circle. Due to low ADC and processor speed, achievable best angular resolution is still limited to 25o.

Postgraduate educational course in radiation protection and the safety of radiation sources. Standard syllabus

International Nuclear Information System (INIS)

2003-01-01

The aim of the Postgraduate Educational Course in Radiation Protection and the Safety of Radiation Sources is to meet the needs of professionals at graduate level, or the equivalent, for initial training to acquire a sound basis in radiation protection and the safety of radiation sources. The course also aims to provide the necessary basic tools for those who will become trainers in radiation protection and in the safe use of radiation sources in their countries. It is designed to provide both theoretical and practical training in the multidisciplinary scientific and/or technical bases of international recommendations and standards on radiation protection and their implementation. The participants should have had a formal education to a level equivalent to a university degree in the physical, chemical or life sciences or engineering and should have been selected to work in the field of radiation protection and the safe use of radiation sources in their countries. The present revision of the Standard Syllabus takes into account the requirements of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), IAEA Safety Series No. 115 (1996) and recommendations of related Safety Guides, as well as experience gained from the Postgraduate Educational Course on Radiation Protection and Safety of Radiation Sources held in several regions in recent years. The general aim of the course, as mentioned, is the same. Some of the improvements in the present version are as follows: The learning objective of each part is specified. The prerequisites for each part are specified. The structure of the syllabus has been changed: the parts on Principles of Radiation Protection and on Regulatory Control were moved ahead of Dose Assessment and after Biological Effects of Radiation. The part on the interface with nuclear safety was dropped and a module on radiation protection in nuclear power plants has been included. A

Postgraduate educational course in radiation protection and the safety of radiation sources. Standard syllabus

International Nuclear Information System (INIS)

2002-01-01

The aim of the Postgraduate Educational Course in Radiation Protection and the Safety of Radiation Sources is to meet the needs of professionals at graduate level, or the equivalent, for initial training to acquire a sound basis in radiation protection and the safety of radiation sources. The course also aims to provide the necessary basic tools for those who will become trainers in radiation protection and in the safe use of radiation sources in their countries. It is designed to provide both theoretical and practical training in the multidisciplinary scientific and/or technical bases of international recommendations and standards on radiation protection and their implementation. The participants should have had a formal education to a level equivalent to a university degree in the physical, chemical or life sciences or engineering and should have been selected to work in the field of radiation protection and the safe use of radiation sources in their countries. The present revision of the Standard Syllabus takes into account the requirements of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), IAEA Safety Series No. 115 (1996) and recommendations of related Safety Guides, as well as experience gained from the Postgraduate Educational Course on Radiation Protection and Safety of Radiation Sources held in several regions in recent years. The general aim of the course, as mentioned, is the same. Some of the improvements in the present version are as follows: The learning objective of each part is specified. The prerequisites for each part are specified. The structure of the syllabus has been changed: the parts on Principles of Radiation Protection and on Regulatory Control were moved ahead of Dose Assessment and after Biological Effects of Radiation. The part on the interface with nuclear safety was dropped and a module on radiation protection in nuclear power plants has been included. A

Incidents with hazardous radiation sources

International Nuclear Information System (INIS)

Schoenhacker, Stefan

2016-01-01

Incidents with hazardous radiation sources can occur in any country, even those without nuclear facilities. Preparedness for such incidents is supposed to fulfill globally agreed minimum standards. Incidents are categorized in incidents with licensed handling of radiation sources as for material testing, transport accidents of hazardous radiation sources, incidents with radionuclide batteries, incidents with satellites containing radioactive inventory, incidents wit not licensed handling of illegally acquired hazardous radiation sources. The emergency planning in Austria includes a differentiation according to the consequences: incidents with release of radioactive materials resulting in restricted contamination, incidents with release of radioactive materials resulting in local contamination, and incidents with the hazard of e@nhanced exposure due to the radiation source.

Regulation for radiation protection in applications of radiation sources

International Nuclear Information System (INIS)

Sonawane, Avinash U.

2016-01-01

Applications of ionising radiation in multifarious field are increasing in the country for the societal benefits. The national regulatory body ensures safety and security of radiation sources by enforcing provisions in the national law and other relevant rules issued under the principle law. In addition, the enforcement of detailed requirements contained in practice specific safety codes and standard and issuance of safety directives brings effectiveness in ensuring safe handling and secure management of radiation sources. The regulatory requirements for control over radiation sources throughout their life-cycle have evolved over the years from experience gained. Nevertheless, some of the regulatory activities which require special attention have been identified such as the development of regulation to deal with advance emerging radiation technology in applications of radiation in medicine and industry; sustaining continuity in ensuring human resource development programme; inspections of category 3 and 4 disused sources and their safe disposal; measures for controlling transboundary movement of radiation sources. The regulatory measures have been contemplated and are being enforced to deal with the above issues in an effective manner. The complete involvement of the management of radiation facilities, radiation workers and their commitment in establishing and maintaining safety and security culture is essential to handle the radiation sources safely and efficiently at all times

Synchrotron radiation sources

Energy Technology Data Exchange (ETDEWEB)

van Steenbergen, A.

1979-01-01

As a result of the exponential growth of the utilization of synchrotron radiation for research in the domain of the material sciences, atomic and molecular physics, biology and technology, a major construction activity has been generated towards new dedicated electron storage rings, designed optimally for synchrotron radiation applications, also, expansion programs are underway at the existing facilities, such as DORIS, SPEAR, and VEPP. In this report the basic properties of synchrotron radiation will be discussed, a short overview will be given of the existing and new facilities, some aspects of the optimization of a structure for a synchrotron radiation source will be discussed and the addition of wigglers and undulators for spectrum enhancement will be described. Finally, some parameters of an optimized synchrotron radiation source will be given.

Three-Dimensional Elasticity Solutions for Sound Radiation of Functionally Graded Materials Plates considering State Space Method

Directory of Open Access Journals (Sweden)

Tieliang Yang

2016-01-01

Full Text Available This paper presents an analytical study for sound radiation of functionally graded materials (FGM plate based on the three-dimensional theory of elasticity. The FGM plate is a mixture of metal and ceramic, and its material properties are assumed to have smooth and continuous variation in the thickness direction according to a power-law distribution in terms of volume fractions of the constituents. Based on the three-dimensional theory of elasticity and state space method, the governing equations with variable coefficients of the FGM plate are derived. The sound radiation of the vibration plate is calculated with Rayleigh integral. Comparisons of the present results with those of solutions in the available literature are made and good agreements are achieved. Finally, some parametric studies are carried out to investigate the sound radiation properties of FGM plates.

Safe handling of radiation sources

International Nuclear Information System (INIS)

Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

2004-01-01

This chapter discussed the subjects related to the safe handling of radiation sources: type of radiation sources, method of use: transport within premises, transport outside premises; Disposal of Gamma Sources

Photoacoustic Sounds from Meteors.

Energy Technology Data Exchange (ETDEWEB)

Spalding, Richard E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tencer, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sweatt, William C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hogan, Roy E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Spurny, Pavel [Academy of Sciences of the Czech Republic (ASCR), Prague (Czech Republic)

2015-03-01

High-speed photometric observations of meteor fireballs have shown that they often produce high-amplitude light oscillations with frequency components in the kHz range, and in some cases exhibit strong millisecond flares. We built a light source with similar characteristics and illuminated various materials in the laboratory, generating audible sounds. Models suggest that light oscillations and pulses can radiatively heat dielectric materials, which in turn conductively heats the surrounding air on millisecond timescales. The sound waves can be heard if the illuminated material is sufficiently close to the observer’s ears. The mechanism described herein may explain many reports of meteors that appear to be audible while they are concurrently visible in the sky and too far away for sound to have propagated to the observer. This photoacoustic (PA) explanation provides an alternative to electrophonic (EP) sounds hypothesized to arise from electromagnetic coupling of plasma oscillation in the meteor wake to natural antennas in the vicinity of an observer.

Sources of pulsed radiation

International Nuclear Information System (INIS)

Sauer, M.C. Jr.

1981-01-01

Characteristics of various sources of pulsed radiation are examined from the viewpoint of their importance to the radiation chemist, and some examples of uses of such sources are mentioned. A summary is given of the application of methods of physical dosimetry to pulsed sources, and the calibration of convenient chemical dosimeters by physical dosimetry is outlined. 7 figures, 1 table

Linear models for sound from supersonic reacting mixing layers

Science.gov (United States)

Chary, P. Shivakanth; Samanta, Arnab

2016-12-01

We perform a linearized reduced-order modeling of the aeroacoustic sound sources in supersonic reacting mixing layers to explore their sensitivities to some of the flow parameters in radiating sound. Specifically, we investigate the role of outer modes as the effective flow compressibility is raised, when some of these are expected to dominate over the traditional Kelvin-Helmholtz (K-H) -type central mode. Although the outer modes are known to be of lesser importance in the near-field mixing, how these radiate to the far-field is uncertain, on which we focus. On keeping the flow compressibility fixed, the outer modes are realized via biasing the respective mean densities of the fast (oxidizer) or slow (fuel) side. Here the mean flows are laminar solutions of two-dimensional compressible boundary layers with an imposed composite (turbulent) spreading rate, which we show to significantly alter the growth of instability waves by saturating them earlier, similar to in nonlinear calculations, achieved here via solving the linear parabolized stability equations. As the flow parameters are varied, instability of the slow modes is shown to be more sensitive to heat release, potentially exceeding equivalent central modes, as these modes yield relatively compact sound sources with lesser spreading of the mixing layer, when compared to the corresponding fast modes. In contrast, the radiated sound seems to be relatively unaffected when the mixture equivalence ratio is varied, except for a lean mixture which is shown to yield a pronounced effect on the slow mode radiation by reducing its modal growth.

Synchroton Radiation Sources

International Nuclear Information System (INIS)

Hulbert, S.L.; Williams, G.P.

1998-01-01

Synchrotron radiation is a very bright, broadband, polarized, pulsed source of light extending from the infrared to the x-ray region. It is an extremely important source of Vacuum Ultraviolet radiation. Brightness is defined as flux per unit area per unit solid angle and is normally a more important quantity than flux alone particularly in throughput limited applications which include those in which monochromators are used. It is well known from classical theory of electricity and magnetism that accelerating charges emit electromagnetic radiation. In the case of synchrotron radiation, relativistic electrons are accelerated in a circular orbit and emit electromagnetic radiation in a broad spectral range. The visible portion of this spectrum was first observed on April 24, 1947 at General Electric's Schenectady facility by Floyd Haber, a machinist working with the synchrotron team, although the first theoretical predictions were by Lienard in the latter part of the 1800's. An excellent early history with references was presented by Blewett and a history covering the development of the utilization of synchrotron radiation was presented by Hartman. Synchrotron radiation covers the entire electromagnetic spectrum from the infrared region through the visible, ultraviolet, and into the x-ray region up to energies of many 10's of kilovolts. If the charged particles are of low mass, such as electrons, and if they are traveling relativistically, the emitted radiation is very intense and highly collimated, with opening angles of the order of 1 milliradian. In electron storage rings there are three possible sources of synchrotron radiation; dipole (bending) magnets; wigglers, which act like a sequence of bending magnets with alternating polarities; and undulators, which are also multi-period alternating magnet systems but in which the beam deflections are small resulting in coherent interference of the emitted light

Acoustic holography for piston sound radiation with non-uniform velocity profiles

NARCIS (Netherlands)

Aarts, R.M.; Janssen, A.J.E.M.

2010-01-01

The theory of orthogonal (Zernike) expansions of functions on a disk, as used in the diffraction theory of optical aberrations, is applied to obtain (semi-) analytical results for the radiation of sound due to a non-uniformly moving, baffled, circular piston. For this particular case, a scheme for

Differences in directional sound source behavior and perception between assorted computer room models

DEFF Research Database (Denmark)

Vigeant, Michelle C.; Wang, Lily M.; Rindel, Jens Holger

2004-01-01

considering reverberation time. However, for the three other parameters evaluated (sound pressure level, clarity index and lateral fraction), the changing diffusivity of the room does not diminish the importance of the directivity. The study therefore shows the importance of considering source directivity......Source directivity is an important input variable when using room acoustic computer modeling programs to generate auralizations. Previous research has shown that using a multichannel anechoic recording can produce a more natural sounding auralization, particularly as the number of channels...

Differences in directional sound source behavior and perception between assorted computer room models

DEFF Research Database (Denmark)

Vigeant, M. C.; Wang, L. M.; Rindel, Jens Holger

2004-01-01

time. However, for the three other parameters evaluated (sound-pressure level, clarity index, and lateral fraction), the changing diffusivity of the room does not diminish the importance of the directivity. The study therefore shows the importance of considering source directivity when using computer......Source directivity is an important input variable when using room acoustic computer modeling programs to generate auralizations. Previous research has shown that using a multichannel anechoic recording can produce a more natural sounding auralization, particularly as the number of channels...

Sound source location in cavitating tip vortices

International Nuclear Information System (INIS)

Higuchi, H.; Taghavi, R.; Arndt, R.E.A.

1985-01-01

Utilizing an array of three hydrophones, individual cavitation bursts in a tip vortex could be located. Theoretically, four hydrophones are necessary. Hence the data from three hydrophones are supplemented with photographic observation of the cavitating tip vortex. The cavitation sound sources are found to be localized to within one base chord length from the hydrofoil tip. This appears to correspond to the region of initial tip vortex roll-up. A more extensive study with a four sensor array is now in progress

The Reduction of Vertical Interchannel Crosstalk: The Analysis of Localisation Thresholds for Natural Sound Sources

Directory of Open Access Journals (Sweden)

Rory Wallis

2017-03-01

Full Text Available In subjective listening tests, natural sound sources were presented to subjects as vertically-oriented phantom images from two layers of loudspeakers, ‘height’ and ‘main’. Subjects were required to reduce the amplitude of the height layer until the position of the resultant sound source matched that of the same source presented from the main layer only (the localisation threshold. Delays of 0, 1 and 10 ms were applied to the height layer with respect to the main, with vertical stereophonic and quadraphonic conditions being tested. The results of the study showed that the localisation thresholds obtained were not significantly affected by sound source or presentation method. Instead, the only variable whose effect was significant was interchannel time difference (ICTD. For ICTD of 0 ms, the median threshold was −9.5 dB, which was significantly lower than the −7 dB found for both 1 and 10 ms. The results of the study have implications both for the recording of sound sources for three-dimensional (3D audio reproduction formats and also for the rendering of 3D images.

Reproduction of nearby sources by imposing true interaural differences on a sound field control approach

DEFF Research Database (Denmark)

Badajoz, Javier; Chang, Ji-ho; Agerkvist, Finn T.

2015-01-01

In anechoic conditions, the Interaural Level Difference (ILD) is the most significant auditory cue to judge the distance to a sound source located within 1 m of the listener's head. This is due to the unique characteristics of a point source in its near field, which result in exceptionally high...... as Pressure Matching (PM), and a binaural control technique. While PM aims at reproducing the incident sound field, the objective of the binaural control technique is to ensure a correct reproduction of interaural differences. The combination of these two approaches gives rise to the following features: (i......, distance dependent ILDs. When reproducing the sound field of sources located near the head with line or circular arrays of loudspeakers, the reproduced ILDs are generally lower than expected, due to physical limitations. This study presents an approach that combines a sound field reproduction method, known...

Improvements on the directional characteristics of a calibration sound source using the Boundary Element Method

DEFF Research Database (Denmark)

Henriquez, Vicente Cutanda; Barrera Figueroa, Salvador; Juhl, Peter Møller

2008-01-01

is of particular importance to achieve a sound field that reaches both microphones with the same level and that is sufficiently uniform at the microphone positions, in order to reduce the effect of misalignment. An existing sound source has been modeled using the Boundary Element Method, and the simulations have......The project Euromet-792 aims to investigate and improve methods for secondary free-field calibration of microphones. In this framework, the comparison method is being studied at DFM in relation to the more usual substitution method of microphone calibration. The design of the sound source...... been used to modify the source and make it suitable for this kind of calibration. It has been found that a central plug, already present in the device, can be re-shaped in such a way that makes the sound field on the microphone positions more uniform, even at rather high frequencies. Measurements have...

Power Difference in Spectrum of Sound Radiation before and after Break of Phantom by Piezoelectric Extracorporeal Shock Wave Lithotriptor

Science.gov (United States)

Kanai, Hiroshi; Jang, Yun-Seok; Chubachi, Noriyoshi; Tanahashi, Yoshikatsu

1994-05-01

This paper investigates the difference in the spectrum of sound radiated before and after the break of a phantom at a focal point of the piezoelectric extracorporeal shock wave lithotriptor (ESWL) in order to identify the break time or to examine whether a calculus exists exactly at the focal point or not. From the preliminary experiments using a piece of chalk as a phantom of a calculus to measure the sound radiated when impact is applied to the chalk by an impact hammer, it is found that the bending vibration component of the vibration is exhibited in the spectrum of sound. However, for small-sized chalk shorter than 3 cm, the peak frequency of the bending vibration is higher than 20 kHz. From the experiments using a piezoeletric ESWL, it is found that there is clear difference in the power spectra among the sound radiated before the break, that radiated just after the break in the breaking process, and that radiated when the chalk does not exist at the focal point of the ESWL. These characteristics will be effective for the examination of the existence of the calculus at the focal point.

Sound Photographs to reveal vehicle pass-by sources with a calibrated source-strength level

NARCIS (Netherlands)

Mast, A.; Dool, T.C. van den; Toorn, J.D. van der; Watts, G.

2003-01-01

In national and European discussions, it appears that the conventional sound measurement techniques are insufficient to answer some relevant questions with respect to source strength of road vehicles. An example of such a question is: What is the importance of tyre-road noise on the one hand and

Inspection of radiation sources and regulatory enforcement (supplement to IAEA Safety Standards Series No. GS-G-1.5)

International Nuclear Information System (INIS)

2010-08-01

The achievement and maintenance of a high level of safety in the use of radiation sources depends on there being a sound legal and governmental infrastructure, including a national regulatory body with well-defined responsibilities and functions. These responsibilities and functions include establishing and implementing a system for carrying out regulatory inspections, and taking necessary enforcement actions. The Safety Requirements publication entitled Legal and Governmental Infrastructure for Nuclear, Radiation, Radioactive Waste and Transport Safety establishes the requirements for legal and governmental infrastructure. The term 'infrastructure' refers to the underlying structure of systems and organizations. This includes requirements concerning the establishment of a regulatory body for radiation sources and the responsibilities and functions assigned to it. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the Basic Safety Standards or the BSS) establish basic requirements for protection against risks associated with exposure to ionizing radiation and for the safety of radiation sources. The application of the BSS is based on the presumption that national infrastructures are in place to enable governments to discharge their responsibilities to for radiation protection and safety. This TECDOC provides practical guidance on the processes for carrying out regulatory inspections and taking enforcement actions. It includes information on the development and use of procedures and standard review plans (i.e. checklists) for inspection. Specific procedures for inspection of radiation practices and sources are provided in the Appendices

Inspection of radiation sources and regulatory enforcement (supplement to IAEA Safety Standards Series No. GS-G-1.5)

International Nuclear Information System (INIS)

2007-04-01

The achievement and maintenance of a high level of safety in the use of radiation sources depends on there being a sound legal and governmental infrastructure, including a national regulatory body with well-defined responsibilities and functions. These responsibilities and functions include establishing and implementing a system for carrying out regulatory inspections, and taking necessary enforcement actions. The Safety Requirements publication entitled Legal and Governmental Infrastructure for Nuclear, Radiation, Radioactive Waste and Transport Safety establishes the requirements for legal and governmental infrastructure. The term 'infrastructure' refers to the underlying structure of systems and organizations. This includes requirements concerning the establishment of a regulatory body for radiation sources and the responsibilities and functions assigned to it. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the Basic Safety Standards or the BSS) establish basic requirements for protection against risks associated with exposure to ionizing radiation and for the safety of radiation sources. The application of the BSS is based on the presumption that national infrastructures are in place to enable governments to discharge their responsibilities to for radiation protection and safety. This TECDOC provides practical guidance on the processes for carrying out regulatory inspections and taking enforcement actions. It includes information on the development and use of procedures and standard review plans (i.e. checklists) for inspection. Specific procedures for inspection of radiation practices and sources are provided in the Appendices

Radiation sources, radiation environment and risk level at Dubna

International Nuclear Information System (INIS)

Komochkov, M.M.

1991-01-01

The overall information about ionizing radiation sources, which form radiation environment and risk at Dubna, is introduced. Systematization of the measurement results is performed on the basis of the effective dose and losses of life expectancy. The contribution of different sources to total harm of Dubna inhabitants has been revealed. JINR sources carry in ∼ 4% from the total effective dose of natural and medicine radiation sources; the harm from them is much less than the harm from cigarette smoking. 18 refs.; 2 tabs

Radiation studies in the antiproton source

International Nuclear Information System (INIS)

Church, M.

1990-01-01

Experiment E760 has a lead glass (Pb-G) calorimeter situated in the antiproton source tunnel in the accumulator ring at location A50. This location is exposed to radiation from several sources during antiproton stacking operations. A series of radiation studies has been performed over the last two years to determine the sources of this radiation and as a result, some shielding has been installed in the antiproton source in order to protect the lead glass from radiation damage

Radiation protection problems with sealed Pu radiation sources

International Nuclear Information System (INIS)

Naumann, M.; Wels, C.

1982-01-01

A brief outline of the production methods and most important properties of Pu-238 and Pu-239 is given, followed by an overview of possibilities for utilizing the different types of radiation emitted, a description of problems involved in the safe handling of Pu radiation sources, and an assessment of the design principles for Pu-containing alpha, photon, neutron and energy sources from the radiation protection point of view. (author)

Community Response to Multiple Sound Sources: Integrating Acoustic and Contextual Approaches in the Analysis

Directory of Open Access Journals (Sweden)

Peter Lercher

2017-06-01

Full Text Available Sufficient data refer to the relevant prevalence of sound exposure by mixed traffic sources in many nations. Furthermore, consideration of the potential effects of combined sound exposure is required in legal procedures such as environmental health impact assessments. Nevertheless, current practice still uses single exposure response functions. It is silently assumed that those standard exposure-response curves accommodate also for mixed exposures—although some evidence from experimental and field studies casts doubt on this practice. The ALPNAP-study population (N = 1641 shows sufficient subgroups with combinations of rail-highway, highway-main road and rail-highway-main road sound exposure. In this paper we apply a few suggested approaches of the literature to investigate exposure-response curves and its major determinants in the case of exposure to multiple traffic sources. Highly/moderate annoyance and full scale mean annoyance served as outcome. The results show several limitations of the current approaches. Even facing the inherent methodological limitations (energy equivalent summation of sound, rating of overall annoyance the consideration of main contextual factors jointly occurring with the sources (such as vibration, air pollution or coping activities and judgments of the wider area soundscape increases the variance explanation from up to 8% (bivariate, up to 15% (base adjustments up to 55% (full contextual model. The added predictors vary significantly, depending on the source combination. (e.g., significant vibration effects with main road/railway, not highway. Although no significant interactions were found, the observed additive effects are of public health importance. Especially in the case of a three source exposure situation the overall annoyance is already high at lower levels and the contribution of the acoustic indicators is small compared with the non-acoustic and contextual predictors. Noise mapping needs to go down to

Sound power emitted by a pure-tone source in a reverberation room

DEFF Research Database (Denmark)

Jacobsen, Finn; Molares, Alfonso Rodriguez

2009-01-01

Energy considerations are of enormous practical importance in acoustics. In "energy acoustics," sources of noise are described in terms of the sound power they emit, the underlying assumption being that this property is independent of the particular environment where the sources are placed. Howev...

Categorization of radiation sources

International Nuclear Information System (INIS)

Antonova, M.

2000-01-01

Through one-parameter (factor) analysis it is proved a hypothesis that the value of a radiation source (RS) activity of an application correlates with the category (the rank) given to it by the IAEA categorization although it is based on other parameters of the RS applications (practices like devices with radiation sources in industry, science, medicine and agriculture). The principles of the new IAEA categorization, taking into account the potential harm the sources may cause and the necessary regulatory control, are described. (author)

Detection of aeroacoustic sound sources on aircraft and wind turbines

NARCIS (Netherlands)

Oerlemans, Stefan

2009-01-01

This thesis deals with the detection of aeroacoustic sound sources on aircraft and wind turbines using phased microphone arrays. First, the reliability of the array technique is assessed using airframe noise measurements in open and closed wind tunnels. It is demonstrated that quantitative acoustic

Natural sources of ionizing radiations

International Nuclear Information System (INIS)

Marej, A.N.

1984-01-01

Natural sources of ionizing radiations are described in detail. The sources are subdivided into sources of extraterrestrial origin (cosmic radiation) and sources of terrestrial origin. Data on the concentration of different nuclides in rocks, various soils, ground waters, atmospheric air, tissues of plants and animals, various food stuffs are presented. The content of natural radionuclides in environmental objects, related to human activities, is discussed

A novel method for direct localized sound speed measurement using the virtual source paradigm

DEFF Research Database (Denmark)

Byram, Brett; Trahey, Gregg E.; Jensen, Jørgen Arendt

2007-01-01

) mediums. The inhomogeneous mediums were arranged as an oil layer, one 6 mm thick and the other 11 mm thick, on top of a water layer. To complement the phantom studies, sources of error for spatial registration of virtual detectors were simulated. The sources of error presented here are multiple sound...... registered virtual detector. Between a pair of registered virtual detectors a spherical wave is propagated. By beamforming the received data the time of flight between the two virtual sources can be calculated. From this information the local sound speed can be estimated. Validation of the estimator used...... both phantom and simulation results. The phantom consisted of two wire targets located near the transducer's axis at depths of 17 and 28 mm. Using this phantom the sound speed between the wires was measured for a homogeneous (water) medium and for two inhomogeneous (DB-grade castor oil and water...

The safe use of radiation sources

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-01

As a means of promoting safety in the use of radiation sources, as well as encouraging consistency in regulatory control, the IAEA has from time to time organized training courses with the co-operation of Member State governments and organizations, to inform individuals from developing countries with appropriate responsibilities on the provisions for the safe use and regulation of radiation sources. Three such courses on the safe use of radiation sources have been held in both the USA, with the co-operation of the United States Government, and in Dublin, Ireland, with the co-operation of the Irish Government. The Training Course on the Safe Use and Regulation of Radiation Sources has been successfully given to over 77 participants from over 30 countries during the last years. The course is aimed at providing a basis of radiation protection knowledge in all aspects of the uses of radiation and of radiation sources that are used today. It is the intention of this course to provide a systematic enhancement of radioisotope safety in countries with developing radiological programmes through a core group of national authorities. The IAEA's training programmes provide an excellent opportunity for direct contact with lecturers that have extensive experience in resolving issues faced by developing countries and in providing guidance documents useful in addressing their problems. This document uses this collective experience and provides valuable technical information regarding the safety aspects of the uses not only of sealed and unsealed sources of radiation, but also for those machines that produce ionizing radiation. The first of these training courses, 'Safety and Regulation of Unsealed Sources' was held in Dublin, Ireland, June through July 1989 with the co-operation of the Nuclear Energy Board and Trinity College. This was an interregional training course, the participants came from all over the world. The second and third interregional courses, 'Safety and Regulation

The safe use of radiation sources

International Nuclear Information System (INIS)

1995-01-01

As a means of promoting safety in the use of radiation sources, as well as encouraging consistency in regulatory control, the IAEA has from time to time organized training courses with the co-operation of Member State governments and organizations, to inform individuals from developing countries with appropriate responsibilities on the provisions for the safe use and regulation of radiation sources. Three such courses on the safe use of radiation sources have been held in both the USA, with the co-operation of the United States Government, and in Dublin, Ireland, with the co-operation of the Irish Government. The Training Course on the Safe Use and Regulation of Radiation Sources has been successfully given to over 77 participants from over 30 countries during the last years. The course is aimed at providing a basis of radiation protection knowledge in all aspects of the uses of radiation and of radiation sources that are used today. It is the intention of this course to provide a systematic enhancement of radioisotope safety in countries with developing radiological programmes through a core group of national authorities. The IAEA's training programmes provide an excellent opportunity for direct contact with lecturers that have extensive experience in resolving issues faced by developing countries and in providing guidance documents useful in addressing their problems. This document uses this collective experience and provides valuable technical information regarding the safety aspects of the uses not only of sealed and unsealed sources of radiation, but also for those machines that produce ionizing radiation. The first of these training courses, 'Safety and Regulation of Unsealed Sources' was held in Dublin, Ireland, June through July 1989 with the co-operation of the Nuclear Energy Board and Trinity College. This was an interregional training course, the participants came from all over the world. The second and third interregional courses, 'Safety and Regulation

Radiation protection and regulatory aspects in the use of radiation sources

International Nuclear Information System (INIS)

Sen, Amit; Dash Sharma, P.K.; Sonawane, A.U.

2012-01-01

The uses of ionising radiation sources (i.e. radioisotopes and radiation generating equipment such as accelerators and X-ray machines) for multifarious applications in industry, medicine, agriculture, research and teaching have been significantly increasing all over the world. In India, the application of radiation sources in various fields has registered phenomenal growth during the last decade. The use of radiation sources mainly include radiation processing for food preservation and sterilization of healthcare products, radiotherapy for treatment of cancer, nuclear medicine for diagnosis and therapy, gamma chambers for several R and D studies, blood irradiators, industrial radiography for non destructive examinations of steel structures, industrial ionising radiation gauging devices for monitoring/measurement of on-line quality control parameters (e.g. thickness, level, density, moisture, elemental analysis), consumer products such as gaseous tritium light sources (GTLS), gaseous tritium light devices (GTLD), ionisation chamber smoke detectors (ICSD), fluorescent light starters, antistatic devices and incandescent gas mantles containing thorium etc. All these beneficial applications involve use of both sealed and unsealed radioactive sources and amount of radioactivity varies from few kBq (μCi) to hundreds of TBq (thousands of curies). Radiation sources emit ionising radiations and if not handled properly and safely, may give rise to potential exposures leading to an unacceptable hazard. Therefore, it is necessary to ensure a high standard of safety and reliability in handling of radiation equipment and sources through their careful design by ensuring adequate built-in-safety as per applicable national/international standard, safe operation and periodic maintenance procedures, safe transport from one place to another, secured storage when not in use, physical security to radiation sources, effective emergency response plans and preparedness, including safe

The role of envelope shape in the localization of multiple sound sources and echoes in the barn owl.

Science.gov (United States)

Baxter, Caitlin S; Nelson, Brian S; Takahashi, Terry T

2013-02-01

Echoes and sounds of independent origin often obscure sounds of interest, but echoes can go undetected under natural listening conditions, a perception called the precedence effect. How does the auditory system distinguish between echoes and independent sources? To investigate, we presented two broadband noises to barn owls (Tyto alba) while varying the similarity of the sounds' envelopes. The carriers of the noises were identical except for a 2- or 3-ms delay. Their onsets and offsets were also synchronized. In owls, sound localization is guided by neural activity on a topographic map of auditory space. When there are two sources concomitantly emitting sounds with overlapping amplitude spectra, space map neurons discharge when the stimulus in their receptive field is louder than the one outside it and when the averaged amplitudes of both sounds are rising. A model incorporating these features calculated the strengths of the two sources' representations on the map (B. S. Nelson and T. T. Takahashi; Neuron 67: 643-655, 2010). The target localized by the owls could be predicted from the model's output. The model also explained why the echo is not localized at short delays: when envelopes are similar, peaks in the leading sound mask corresponding peaks in the echo, weakening the echo's space map representation. When the envelopes are dissimilar, there are few or no corresponding peaks, and the owl localizes whichever source is predicted by the model to be less masked. Thus the precedence effect in the owl is a by-product of a mechanism for representing multiple sound sources on its map.

Control of radiation sources in Japan

International Nuclear Information System (INIS)

Maki, S.

2001-01-01

The report refers to the regulations for radioactive material in force in Japan, and to the organizations with responsibilities for regulating radiation sources. An outline of the law regulating the use of radiation sources and radioactive materials is provided, including its scope, types of radiation sources under control, exemptions and the system of notification, authorization and inspection. The experience of Japan with orphan sources is presented in three different cases, and the measures carried out to store the orphan sources in safe conditions. (author)

Searching for Orphan radiation sources

International Nuclear Information System (INIS)

Bystrov, Evgenij; Antonau, Uladzimir; Gurinovich, Uladzimir; Kazhamiakin, Valery; Petrov, Vitaly; Shulhovich, Heorhi; Tischenko, Siarhei

2008-01-01

Full text: The problem of orphan sources cannot be left unaddressed due high probability of accidental exposure and use of sources for terrorism. Search of objects of this kind is complex particularly when search territory is large. This requires devices capable of detecting sources, identifying their radionuclide composition, and correlating scan results to geographical coordinates and displaying results on a map. Spectral radiation scanner AT6101C can fulfill the objective of search for gamma and neutron radiation sources, radionuclide composition identification, correlation results to geographical coordinates and displaying results on a map. The scanner consists of gamma radiation scintillation detection unit based on NaI(Tl) crystal, neutron detection unit based on two He 3 counters, GPS receiver and portable ruggedized computer. Built-in and application software automates entire scan process, saving all results to memory for further analysis with visual representation of results as spectral information diagrams, count rate profile and gamma radiation dose rates on a geographical map. The scanner informs operator with voice messages on detection of radiation sources, identification result and other events. Scanner detection units and accessories are packed in a backpack. Weighing 7 kg, the scanner is human portable and can be used for scan inside cars. The scanner can also be used for radiation mapping and inspections. (author)

Experience with synchrotron radiation sources

International Nuclear Information System (INIS)

Krinsky, S.

1987-01-01

The development of synchrotron radiation sources is discussed, emphasizing characteristics important for x-ray microscopy. Bending magnets, wigglers and undulators are considered as sources of radiation. Operating experience at the national Synchrotron Light Source on the VUV and XRAY storage rings is reviewed, with particular consideration given to achieved current and lifetime, transverse bunch dimensions, and orbit stability. 6 refs., 3 figs

The sources of radiation exposure

International Nuclear Information System (INIS)

Bennett, B.G.

1992-01-01

Radiation protection of workers and of members of the public requires an assessment of the various sources of exposure, their variations in time or under specific conditions or circumstances, and the possibilities for control or limitation. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has evaluated the various components of natural and man-made sources in some detail. Natural exposures form the largest component of radiation exposure of man. Variability in exposures depends on elevation, the concentrations of radionuclides in soil, food and water, the composition of building materials and the susceptibility of indoor spaces to radon build-up. Man-made sources have included exposures to fallout from atmospheric nuclear testing and discharged from nuclear fuel cycle installations in routine operations or in accidents. The other main source of radiation exposures of individuals is in medical diagnostic examinations and therapeutic treatments. (author)

Perceptual assessment of quality of urban soundscapes with combined noise sources and water sounds.

Science.gov (United States)

Jeon, Jin Yong; Lee, Pyoung Jik; You, Jin; Kang, Jian

2010-03-01

In this study, urban soundscapes containing combined noise sources were evaluated through field surveys and laboratory experiments. The effect of water sounds on masking urban noises was then examined in order to enhance the soundscape perception. Field surveys in 16 urban spaces were conducted through soundwalking to evaluate the annoyance of combined noise sources. Synthesis curves were derived for the relationships between noise levels and the percentage of highly annoyed (%HA) and the percentage of annoyed (%A) for the combined noise sources. Qualitative analysis was also made using semantic scales for evaluating the quality of the soundscape, and it was shown that the perception of acoustic comfort and loudness was strongly related to the annoyance. A laboratory auditory experiment was then conducted in order to quantify the total annoyance caused by road traffic noise and four types of construction noise. It was shown that the annoyance ratings were related to the types of construction noise in combination with road traffic noise and the level of the road traffic noise. Finally, water sounds were determined to be the best sounds to use for enhancing the urban soundscape. The level of the water sounds should be similar to or not less than 3 dB below the level of the urban noises.

Acoustic resonators for the reduction of sound radiation and transmission

NARCIS (Netherlands)

Hannink, M.H.C.

2007-01-01

Noise is a frequently encountered problem in modern society. One of the environments where the presence of noise causes a deterioration in people’s comfort is in aircraft cabins. For modern aircraft flying at cruise conditions, the main sound source is the turbulent boundary layer around the

Aerofoil broadband and tonal noise modelling using stochastic sound sources and incorporated large scale fluctuations

Science.gov (United States)

Proskurov, S.; Darbyshire, O. R.; Karabasov, S. A.

2017-12-01

The present work discusses modifications to the stochastic Fast Random Particle Mesh (FRPM) method featuring both tonal and broadband noise sources. The technique relies on the combination of incorporated vortex-shedding resolved flow available from Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation with the fine-scale turbulence FRPM solution generated via the stochastic velocity fluctuations in the context of vortex sound theory. In contrast to the existing literature, our method encompasses a unified treatment for broadband and tonal acoustic noise sources at the source level, thus, accounting for linear source interference as well as possible non-linear source interaction effects. When sound sources are determined, for the sound propagation, Acoustic Perturbation Equations (APE-4) are solved in the time-domain. Results of the method's application for two aerofoil benchmark cases, with both sharp and blunt trailing edges are presented. In each case, the importance of individual linear and non-linear noise sources was investigated. Several new key features related to the unsteady implementation of the method were tested and brought into the equation. Encouraging results have been obtained for benchmark test cases using the new technique which is believed to be potentially applicable to other airframe noise problems where both tonal and broadband parts are important.

Sources of radiation exposure - an overview

International Nuclear Information System (INIS)

Mason, G.C.

1990-01-01

Sources of radiation exposure are reviewed from the perspective of mining and milling of radioactive ores in Australia. The major sources of occupational and public exposure are identified and described, and exposures from mining and milling operations are discussed in the context of natural radiation sources and other sources arising from human activities. Most radiation exposure of humans comes from natural sources. About 80% of the world average of the effective dose equivalents received by individual people arises from natural radiation, with a further 15-20% coming from medical exposures*. Exposures results from human activities, such as mining and milling of radioactive ores, nuclear power generation, fallout from nuclear weapons testing and non-medical use of radioisotopes and X-rays, add less than 1% to the total. 9 refs., 4 tabs., 10 figs

Maximum likelihood approach to “informed” Sound Source Localization for Hearing Aid applications

DEFF Research Database (Denmark)

Farmani, Mojtaba; Pedersen, Michael Syskind; Tan, Zheng-Hua

2015-01-01

Most state-of-the-art Sound Source Localization (SSL) algorithms have been proposed for applications which are "uninformed'' about the target sound content; however, utilizing a wireless microphone worn by a target talker, enables recent Hearing Aid Systems (HASs) to access to an almost noise......-free sound signal of the target talker at the HAS via the wireless connection. Therefore, in this paper, we propose a maximum likelihood (ML) approach, which we call MLSSL, to estimate the Direction of Arrival (DoA) of the target signal given access to the target signal content. Compared with other "informed...

Detection of aeroacoustic sound sources on aircraft and wind turbines

International Nuclear Information System (INIS)

Oerlemans, S.

2009-01-01

This thesis deals with the detection of aeroacoustic sound sources on aircraft and wind turbines using phased microphone arrays. First, the reliability of the array technique is assessed using airframe noise measurements in open and closed wind tunnels. It is demonstrated that quantitative acoustic measurements are possible in both wind tunnels. Then, the array technique is applied to characterize the noise sources on two modern large wind turbines. It is shown that practically all noise emitted to the ground is produced by the outer part of the blades during their downward movement. This asymmetric source pattern, which causes the typical swishing noise during the passage of the blades, can be explained by trailing edge noise directivity and convective amplification. Next, a semi-empirical prediction method is developed for the noise from large wind turbines. The prediction code is successfully validated against the experimental results, not only with regard to sound levels, spectra, and directivity, but also with regard to the noise source distribution in the rotor plane and the temporal variation in sound level (swish). The validated prediction method is then applied to calculate wind turbine noise footprints, which show that large swish amplitudes can occur even at large distance. The influence of airfoil shape on blade noise is investigated through acoustic wind tunnel tests on a series of wind turbine airfoils. Measurements are carried out at various wind speeds and angles of attack, with and without upstream turbulence and boundary layer tripping. The speed dependence, directivity, and tonal behaviour are determined for both trailing edge noise and inflow turbulence noise. Finally, two noise reduction concepts are tested on a large wind turbine: acoustically optimized airfoils and trailing edge serrations. Both blade modifications yield a significant trailing edge noise reduction at low frequencies, but also cause increased tip noise at high frequencies

Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

Energy Technology Data Exchange (ETDEWEB)

Scott Wilde, Raymond Keegan

2008-07-01

The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

Regulatory control of radiation sources in Slovakia

International Nuclear Information System (INIS)

Auxtova, L.

2001-01-01

In Slovakia, there are two regulatory authorities. Regulatory control of the utilization of nuclear energy, based on the Slovak National Council's law No. 130/1998 on the peaceful uses of nuclear energy, is exercised by the Nuclear Regulatory Authority of the Slovak Republic. The second regulatory authority - the Ministry of Health - is empowered by law No. 72/1994 on the protection of human health to license radiation sources and is responsible for radiation protection supervision (there are nearly 3000 establishments with sealed sources, radiation generators and unsealed sources in Slovakia). Pursuant to a new radiation protection regulation based on international standards, radiation sources are to be categorized in six classes according to the associated exposure and contamination hazards. A national strategy for improving the safety of radiation sources over their life-cycle and for the management of disused and orphan sources is being prepared for governmental approval. (author)

Sound transmission analysis of plate structures using the finite element method and elementary radiator approach with radiator error index

DEFF Research Database (Denmark)

Jung, Jaesoon; Kook, Junghwan; Goo, Seongyeol

2017-01-01

combines the FEM and Elementary Radiator Approach (ERA) is proposed. The FE-ERA method analyzes the vibrational response of the plate structure excited by incident sound using FEM and then computes the transmitted acoustic pressure from the vibrating plate using ERA. In order to improve the accuracy...... and efficiency of the FE-ERA method, a novel criterion for the optimal number of elementary radiators is proposed. The criterion is based on the radiator error index that is derived to estimate the accuracy of the computation with used number of radiators. Using the proposed criterion a radiator selection method...... is presented for determining the optimum number of radiators. The presented radiator selection method and the FE-ERA method are combined to improve the computational accuracy and efficiency. Several numerical examples that have been rarely addressed in previous studies, are presented with the proposed method...

Near-field acoustic holography with sound pressure and particle velocity measurements

DEFF Research Database (Denmark)

Fernandez Grande, Efren

of the particle velocity has notable potential in NAH, and furthermore, combined measurement of sound pressure and particle velocity opens a new range of possibilities that are examined in this study. On this basis, sound field separation methods have been studied, and a new measurement principle based on double...... layer measurements of the particle velocity has been proposed. Also, the relation between near-field and far-field radiation from sound sources has been examined using the concept of the supersonic intensity. The calculation of this quantity has been extended to other holographic methods, and studied...

Synthesis of Room Impulse Responses for Variable Source Characteristics

Directory of Open Access Journals (Sweden)

M. Kunkemoeller

2011-01-01

Full Text Available Every acoustic source, e.g. a speaker, a musical instrument or a loudspeaker, generally has a frequency dependent characteristic radiation pattern, which is preeminent at higher frequencies. Room acoustic measurements nowadays only account for omnidirectional source characteristics. This motivates a measurement method that is capable of obtaining room impulse responses for these specific radiation patterns by using a superposition approach of several measurements with technically well-defined sound sources. We propose a method based on measurements with a 12-channel independentlydriven dodecahedron loudspeaker array rotated by an automatically controlled turntable.Radiation patterns can be efficiently described with the use of spherical harmonics representation. We propose a method that uses this representation for the spherical loudspeaker array used for the measurements and the target radiation pattern to be used for the synthesis.We show validating results for a deterministic test sound source inside in a small lecture hall.

The influence of signal parameters on the sound source localization ability of a harbor porpoise (Phocoena phocoena)

NARCIS (Netherlands)

Kastelein, R.A.; Haan, D.de; Verboom, W.C.

2007-01-01

It is unclear how well harbor porpoises can locate sound sources, and thus can locate acoustic alarms on gillnets. Therefore the ability of a porpoise to determine the location of a sound source was determined. The animal was trained to indicate the active one of 16 transducers in a 16-m -diam

76 FR 6692 - Radiation Sources on Army Land

Science.gov (United States)

2011-02-08

... possession of ionizing radiation sources by non-Army entities (including their civilian contractors) on an... Radiation Permit (ARP) from the garrison commander to use, store, or possess ionizing radiation sources on an Army installation. For the purpose of this rule, ``ionizing radiation source'' means any source...

Radiation measurement practice for understanding statistical fluctuation of radiation count using natural radiation sources

International Nuclear Information System (INIS)

Kawano, Takao

2014-01-01

It is known that radiation is detected at random and the radiation counts fluctuate statistically. In the present study, a radiation measurement experiment was performed to understand the randomness and statistical fluctuation of radiation counts. In the measurement, three natural radiation sources were used. The sources were fabricated from potassium chloride chemicals, chemical fertilizers and kelps. These materials contain naturally occurring potassium-40 that is a radionuclide. From high schools, junior high schools and elementary schools, nine teachers participated to the radiation measurement experiment. Each participant measured the 1-min integration counts of radiation five times using GM survey meters, and 45 sets of data were obtained for the respective natural radiation sources. It was found that the frequency of occurrence of radiation counts was distributed according to a Gaussian distribution curve, although the obtained 45 data sets of radiation counts superficially looked to be fluctuating meaninglessly. (author)

Towards a Synesthesia Laboratory: Real-time Localization and Visualization of a Sound Source for Virtual Reality Applications

OpenAIRE

Kose, Ahmet; Tepljakov, Aleksei; Astapov, Sergei; Draheim, Dirk; Petlenkov, Eduard; Vassiljeva, Kristina

2018-01-01

In this paper, we present our findings related to the problem of localization and visualization of a sound source placed in the same room as the listener. The particular effect that we aim to investigate is called synesthesia—the act of experiencing one sense modality as another, e.g., a person may vividly experience flashes of colors when listening to a series of sounds. Towards that end, we apply a series of recently developed methods for detecting sound source in a three-dimensional space ...

Modeling Noise Sources and Propagation in External Gear Pumps

Directory of Open Access Journals (Sweden)

Sangbeom Woo

2017-07-01

Full Text Available As a key component in power transfer, positive displacement machines often represent the major source of noise in hydraulic systems. Thus, investigation into the sources of noise and discovering strategies to reduce noise is a key part of improving the performance of current hydraulic systems, as well as applying fluid power systems to a wider range of applications. The present work aims at developing modeling techniques on the topic of noise generation caused by external gear pumps for high pressure applications, which can be useful and effective in investigating the interaction between noise sources and radiated noise and establishing the design guide for a quiet pump. In particular, this study classifies the internal noise sources into four types of effective load functions and, in the proposed model, these load functions are applied to the corresponding areas of the pump case in a realistic way. Vibration and sound radiation can then be predicted using a combined finite element and boundary element vibro-acoustic model. The radiated sound power and sound pressure for the different operating conditions are presented as the main outcomes of the acoustic model. The noise prediction was validated through comparison with the experimentally measured sound power levels.

A SOUND SOURCE LOCALIZATION TECHNIQUE TO SUPPORT SEARCH AND RESCUE IN LOUD NOISE ENVIRONMENTS

Science.gov (United States)

Yoshinaga, Hiroshi; Mizutani, Koichi; Wakatsuki, Naoto

At some sites of earthquakes and other disasters, rescuers search for people buried under rubble by listening for the sounds which they make. Thus developing a technique to localize sound sources amidst loud noise will support such search and rescue operations. In this paper, we discuss an experiment performed to test an array signal processing technique which searches for unperceivable sound in loud noise environments. Two speakers simultaneously played a noise of a generator and a voice decreased by 20 dB (= 1/100 of power) from the generator noise at an outdoor space where cicadas were making noise. The sound signal was received by a horizontally set linear microphone array 1.05 m in length and consisting of 15 microphones. The direction and the distance of the voice were computed and the sound of the voice was extracted and played back as an audible sound by array signal processing.

Radiation safety and inventory of sealed radiation sources in Pakistan

International Nuclear Information System (INIS)

Ali, M.; Mannan, A.

2001-01-01

Sealed radiation sources (SRS) of various types and activities are widely used in industry, medicine, agriculture, research and teaching in Pakistan. The proper maintenance of records of SRS is mandatory for users/licensees. Since 1956, more than 2000 radiation sources of different isotopes having activities of Bq to TBq have been imported. Of these, several hundred sources have been disposed of and some have been exported/returned to the suppliers. To ensure the safety and security of the sources and to control and regulate the safe use of radiation sources in various disciplines, the Directorate of Nuclear Safety and Radiation Protection (DNSRP), the implementing arm of the regulatory authority in the country, has introduced a system for notifying, registering and licensing the use of all types of SRS. In order to update the inventory of SRS used throughout the country, the DNSRP has developed a database. (author)

Doses from Medical Radiation Sources

Science.gov (United States)

... Medical Radiation Sources Michael G. Stabin, PhD, CHP Introduction Radiation exposures from diagnostic medical examinations are generally ... of exposure annually to natural background radiation. Plain Film X Rays Single Radiographs Effective Dose, mSv Skull ( ...

Sound Spectrum Influences Auditory Distance Perception of Sound Sources Located in a Room Environment

Directory of Open Access Journals (Sweden)

Ignacio Spiousas

2017-06-01

Full Text Available Previous studies on the effect of spectral content on auditory distance perception (ADP focused on the physically measurable cues occurring either in the near field (low-pass filtering due to head diffraction or when the sound travels distances >15 m (high-frequency energy losses due to air absorption. Here, we study how the spectrum of a sound arriving from a source located in a reverberant room at intermediate distances (1–6 m influences the perception of the distance to the source. First, we conducted an ADP experiment using pure tones (the simplest possible spectrum of frequencies 0.5, 1, 2, and 4 kHz. Then, we performed a second ADP experiment with stimuli consisting of continuous broadband and bandpass-filtered (with center frequencies of 0.5, 1.5, and 4 kHz and bandwidths of 1/12, 1/3, and 1.5 octave pink-noise clips. Our results showed an effect of the stimulus frequency on the perceived distance both for pure tones and filtered noise bands: ADP was less accurate for stimuli containing energy only in the low-frequency range. Analysis of the frequency response of the room showed that the low accuracy observed for low-frequency stimuli can be explained by the presence of sparse modal resonances in the low-frequency region of the spectrum, which induced a non-monotonic relationship between binaural intensity and source distance. The results obtained in the second experiment suggest that ADP can also be affected by stimulus bandwidth but in a less straightforward way (i.e., depending on the center frequency, increasing stimulus bandwidth could have different effects. Finally, the analysis of the acoustical cues suggests that listeners judged source distance using mainly changes in the overall intensity of the auditory stimulus with distance rather than the direct-to-reverberant energy ratio, even for low-frequency noise bands (which typically induce high amount of reverberation. The results obtained in this study show that, depending on

The regulatory control of radiation sources in Turkey

International Nuclear Information System (INIS)

Uslu, I.; Birol, E.

2001-01-01

In Turkey, the national competent authority for regulating activities involving radioactive sources is the Turkish Atomic Energy Authority, which implements the responsibility for the safety and security of radiation sources through its Radiation Health and Safety Department. The report describes the organization of the regulatory infrastructure for radiation safety in Turkey and, after a brief explanation of the current legal framework for such purpose, it refers to how the management of radiation sources is carried out and to the new provisions regarding radiation sources, including inspections of licensees and training on source safety. Finally, the report provides information on the Ikitelli radiological accident in Turkey and the current public concern about radiation sources after it happened. (author)

Notification and authorization for the use of radiation sources (supplement to IAEA Safety Standards Series No. GS-G-1.5)

International Nuclear Information System (INIS)

2007-04-01

The achievement and maintenance of a high level of safety in the use of radiation sources depend on there being a sound legal and governmental infrastructure, including a national regulatory body with well-defined responsibilities and functions. These responsibilities and functions include establishing and implementing a system for notification and authorization for control over radiation sources, including a system for review and assessment of applications for authorization. The Safety Requirements publication entitled Legal and Governmental Infrastructure for Nuclear, Radiation, Radioactive Waste and Transport Safety establishes the requirements for legal and governmental infrastructure. The term 'infrastructure' refers to the underlying structure of systems and organizations. This includes requirements concerning the establishment of a regulatory body for radiation sources and the responsibilities and functions assigned to it. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the Basic Safety Standards or the BSS) establish basic requirements for protection against risks associated with exposure to ionizing radiation and for the safety of radiation sources. The application of the BSS is based on the presumption that national infrastructures are in place to enable governments to discharge their responsibilities to for radiation protection and safety. This TECDOC provides practical guidance on the process for dealing with applications for authorization and accepting notifications to regulatory bodies. Examples of guidelines that may be used by persons required to notify or apply for authorization and of the regulatory body's review and assessment procedures are provided in the Appendices. The TECDOC is oriented towards national regulatory infrastructures concerned with protection and safety for radiation sources used in medicine, industry, agriculture, research and education

Notification and authorization for the use of radiation sources (supplement to IAEA Safety Standards Series No. GS-G-1.5)

International Nuclear Information System (INIS)

2010-10-01

The achievement and maintenance of a high level of safety in the use of radiation sources depend on there being a sound legal and governmental infrastructure, including a national regulatory body with well-defined responsibilities and functions. These responsibilities and functions include establishing and implementing a system for notification and authorization for control over radiation sources, including a system for review and assessment of applications for authorization. The Safety Requirements publication entitled Legal and Governmental Infrastructure for Nuclear, Radiation, Radioactive Waste and Transport Safety establishes the requirements for legal and governmental infrastructure. The term 'infrastructure' refers to the underlying structure of systems and organizations. This includes requirements concerning the establishment of a regulatory body for radiation sources and the responsibilities and functions assigned to it. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the Basic Safety Standards or the BSS) establish basic requirements for protection against risks associated with exposure to ionizing radiation and for the safety of radiation sources. The application of the BSS is based on the presumption that national infrastructures are in place to enable governments to discharge their responsibilities to for radiation protection and safety. This TECDOC provides practical guidance on the process for dealing with applications for authorization and accepting notifications to regulatory bodies. Examples of guidelines that may be used by persons required to notify or apply for authorization and of the regulatory body's review and assessment procedures are provided in the Appendices. The TECDOC is oriented towards national regulatory infrastructures concerned with protection and safety for radiation sources used in medicine, industry, agriculture, research and education

Management of Spent Radiation Source from Radiotherapy

International Nuclear Information System (INIS)

Aisyah

2008-01-01

Nowadays the use of radioactive source for both radiodiagnostic and radiotherapy in Indonesia hospital increases rapidly. Sealed source used in radiotherapy among others for brachytherapy, teletherapy, bone densitometry, whole blood irradiation and gamma knife (radiosurgery). In line with this, the waste of spent radiation sources will be generated in hospitals. Of course these spent radiation sources must be treated correctly in order to maintain the safety of both the public and the environment. According to the Act No. 10/1997, BATAN, in care of the Radioactive Waste Management Center is the national appointed agency for the management of radioactive waste. The option for waste management by hospitals needs to be expound, either by re-exporting to the supplier of origin, re-exporting to other supplier, re-use by other licensee or sending to the Radioactive Waste Management Center. Usually the waste sent by the hospitals to the center comprises of sealed radiation source of 60 Co, 137 Cs or 226 Ra. The management of spent radiation source in the center is carried out in several steps i.e. conditioning, temporary storage, and long-term storage (final disposal). The conditioning of non 226 Ra is carried out by placing the waste in a 200 litter drum shell, 950 or 350 litter concrete shells, depends on the activity and dimension of the spent radiation source. The conditioning of 226 Ra is carried out by encapsulating the waste in a stainless steel container for long-term storage shield which then placed in a 200 litter drum shell. The temporary storage of the conditioned spent radiation source is carried out by storing it in the center’s temporary storages, either low or medium activity waste. Finally, the conditioned spent radiation source is buried in a disposal facility. For medium half-life spent radiation source, the final disposal is burial it in a shallow-land disposal; mean while, for long half-life spent radiation source, the final disposal is burial it in

Numerical design and testing of a sound source for secondary calibration of microphones using the Boundary Element Method

DEFF Research Database (Denmark)

Cutanda Henriquez, Vicente; Juhl, Peter Møller; Barrera Figueroa, Salvador

2009-01-01

Secondary calibration of microphones in free field is performed by placing the microphone under calibration in an anechoic chamber with a sound source, and exposing it to a controlled sound field. A calibrated microphone is also measured as a reference. While the two measurements are usually made...... apart to avoid acoustic interaction. As a part of the project Euromet-792, aiming to investigate and improve methods for secondary free-field calibration of microphones, a sound source suitable for simultaneous secondary free-field calibration has been designed using the Boundary Element Method...... of the Danish Fundamental Metrology Institute (DFM). The design and verification of the source are presented in this communication....

New sources of radiation

International Nuclear Information System (INIS)

Schimmerling, W.

1979-09-01

An attempt is made to select examples of radiation sources whose application may make new or unconventional demands on radiation protection and dosimetry. A substantial body of knowledge about high energy facilities exists and, partly for this reason, the great high energy accelerators are mentioned only briefly

Notification and authorization for the use of radiation sources (Supplement to IAEA Safety Standards Series No. GS-G-1.5)

International Nuclear Information System (INIS)

2011-10-01

The achievement and maintenance of a high level of safety in the use of radiation sources depend on there being a sound legal and governmental infrastructure, including a national regulatory body with well-defined responsibilities and functions. These responsibilities and functions include establishing and implementing a system for notification and authorization for control over radiation sources, including a system for review and assessment of applications for authorization. The Safety Requirements publication entitled Legal and Governmental Infrastructure for Nuclear, Radiation, Radioactive Waste and Transport Safety establishes the requirements for legal and governmental infrastructure. The term 'infrastructure' refers to the underlying structure of systems and organizations. This includes requirements concerning the establishment of a regulatory body for radiation sources and the responsibilities and functions assigned to it. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the Basic Safety Standards or the BSS) establish basic requirements for protection against risks associated with exposure to ionizing radiation and for the safety of radiation sources. The application of the BSS is based on the presumption that national infrastructures are in place to enable governments to discharge their responsibilities to for radiation protection and safety. This TECDOC provides practical guidance on the process for dealing with applications for authorization and accepting notifications to regulatory bodies. Examples of guidelines that may be used by persons required to notify or apply for authorization and of the regulatory body's review and assessment procedures are provided in the Appendices. The TECDOC is oriented towards national regulatory infrastructures concerned with protection and safety for radiation sources used in medicine, industry, agriculture, research and education. The IAEA

Apparatus for radiation source depth determination in a material

International Nuclear Information System (INIS)

Campbell, P.J.

1979-01-01

An apparatus is disclosed for determining the depth of a radiation source within a body of material utilizing a radiation source holder moving the radiation source within the body. A plurality of switches have contacts that are fixed in relation to the movement of the radiation source within the material. Trigger means activates a particular switch at a preselected depth of the radiation source. Means for indicating the activation of a switch would thus produce a signal as a representative of the depth of the radiation source

High energy particle accelerators as radiation Sources

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, M E [National Center for Nuclear Safety and Radiation Vontrol, Atomic Energy Authority, Cairo (Egypt)

1997-12-31

Small accelerators in the energy range of few million electron volts are usually used as radiation sources for various applications, like radiotherapy, food irradiation, radiation sterilization and in other industrial applications. High energy accelerators with energies reaching billions of electron volts also find wide field of applications as radiation sources. Synchrotrons with high energy range have unique features as radiation sources. This review presents a synopsis of cyclic accelerators with description of phase stability principle of high energy accelerators with emphasis on synchrotrons. Properties of synchrotron radiation are given together with their applications in basic and applied research. 13 figs.,1 tab.

Photon acceleration-based radiation sources

International Nuclear Information System (INIS)

Hoffman, J. R.; Muggli, P.; Katsouleas, T.; Mori, W. B.; Joshi, C.

1999-01-01

The acceleration and deceleration of photons in a plasma provides the means for a series of new radiation sources. Previous work on a DC to AC Radiation Converter (DARC source) has shown variable acceleration of photons having zero frequency (i.e., an electrostatic field) to between 6 and 100 GHz (1-3). These sources all had poor guiding characteristics resulting in poor power coupling from the source to the load. Continuing research has identified a novel way to integrate the DARC source into a waveguide. The so called ''pin structure'' uses stainless steel pins inserted through the narrow side of an X band waveguide to form the electrostatic field pattern (k≠0, ω=0). The pins are spaced such that the absorption band resulting from this additional periodic structure is outside of the X band range (8-12 GHz), in which the normal waveguide characteristics are left unchanged. The power of this X band source is predicted theoretically to scale quadratically with the pin bias voltage as -800 W/(kV) 2 and have a pulse width of -1 ns. Cold tests and experimental results are presented. Applications for a high power, short pulse radiation source extends to the areas of landmine detection, improved radar resolution, and experimental investigations of molecular systems

The Encoding of Sound Source Elevation in the Human Auditory Cortex.

Science.gov (United States)

Trapeau, Régis; Schönwiesner, Marc

2018-03-28

tuning functions in low-level auditory cortex underlie the perceived elevation of a sound source. Copyright © 2018 the authors 0270-6474/18/383252-13$15.00/0.

Sound radiation contrast in MR phase images. Method for the representation of elasticity, sound damping, and sound impedance changes

International Nuclear Information System (INIS)

Radicke, Marcus

2009-01-01

The method presented in this thesis combines ultrasound techniques with the magnetic-resonance tomography (MRT). An ultrasonic wave generates in absorbing media a static force in sound-propagation direction. The force leads at sound intensities of some W/cm 2 and a sound frequency in the lower MHz range to a tissue shift in the micrometer range. This tissue shift depends on the sound power, the sound frequency, the sound absorption, and the elastic properties of the tissue. A MRT sequence of the Siemens Healthcare AG was modified so that it measures (indirectly) the tissue shift, codes as grey values, and presents as 2D picture. By means of the grey values the sound-beam slope in the tissue can be visualized, and so additionally sound obstacles (changes of the sound impedance) can be detected. By the MRT images token up spatial changes of the tissue parameters sound absorption and elasticity can be detected. In this thesis measurements are presented, which show the feasibility and future chances of this method especially for the mammary-cancer diagnostics. [de

Safe management of spent radiation source

International Nuclear Information System (INIS)

Kosako, Toshiso; Sugiura, Nobuyuki; Valdezco, E.M.; Choi, Kwang-Sub

2003-01-01

Presented are 8 investigation reports concerning the safe management of spent radiation source (SRS) during the current 2 years. Four reports from Japan are: Scheme for SRS management (approach and present status of the SRS management and consideration toward solving problems); Current International Atomic Energy Agency (IAEA) activities related to safety of radiation sources (Chronology of action plan development, Outline of revised action plan, and Asian regional activities); Current status of SRS management in Japan (Regulation system, Obligations of licensed users, Regulatory system on sealed sources, Status in the incidents on sources occurred, Incident of source loss, and Incidents of orphan sources); and SRS management system in Japan (Current status of using of sealed sources, collection system of SRS-Japan Radioisotope Association (JRIA) services, and Disposal of SRS). Four reports from the Asian countries also concern the current statuses of SRS management in the Philippine (Radioactive waste sources, Waste management strategies, Conditioning of Ra sources, Ra project action plan, as low as reasonably achievable (ALARA) program, Dose assessment, Regulations on radioactive waste, Action plan on the safety and security of sources, IAEA Regional Demonstration Centers, and sitting studies for a near surface disposal facility); Thailand (Current status of using sealed sources, Inventory of SRS, and Current topics of SRS management); Indonesia (Principles of management of radiation sources, Legislative framework of SRS management practices, Regulatory on SRS, management of sealed SRS, management hurdles, and reported incidents); and Korea (Regulatory frame work, Collection systems of SRS, Radioisotope waste generation, Radiation exposure incident, and Scrap monitoring system). (N.I.)

Radiation protection and the safety of radiation sources

International Nuclear Information System (INIS)

1996-01-01

These Safety Fundamentals cover the protection of human beings against ionizing radiation (gamma and X rays and alpha, beta and other particles that can induce ionization as they interact with biological materials), referred to herein subsequently as radiation, and the safety of sources that produce ionizing radiation. The Fundamentals do not apply to non-ionizing radiation such as microwave, ultraviolet, visible and infrared radiation. They do not apply either to the control of non-radiological aspects of health and safety. They are, however, part of the overall framework of health and safety

Radiation sources safety and radioactive materials security regulation in Ukraine

International Nuclear Information System (INIS)

Smyshliaiev, A.; Holubiev, V.; Makarovska, O.

2001-01-01

Radiation sources are widely used in Ukraine. There are about 2500 users in industry, science, education and about 2800 in medicine. About 80,000 sealed radiation sources with total kerma-equivalent of 450 Gy*M 2 /sec are used in Ukraine. The exact information about the radiation sources and their users will be provided in 2001 after the expected completion of the State inventory of radiation sources in Ukraine. In order to ensure radiation source safety in Ukraine, a State System for regulation of activities dealing with radiation sources has been established. The system includes the following elements: establishment of norms, rules and standards of radiation safety; authorization activity, i.e. issuance of permits (including those in the form of licences) for activities dealing with radiation sources; supervisory activity, i.e. control over observance of norms, rules and standards of radiation safety and fulfilment of conditions of licences for activities dealing with radiation sources, and also enforcement. Comprehensive nuclear legislation was developed and implemented from 1991 to 2000. Radiation source safety is regulated by three main nuclear laws in Ukraine: On the use of nuclear energy and radiation safety (passed on 8 February 1995); On Human Protection from Impact of Ionizing Radiation (passed on 14 January 1998); On permissive activity in the area of nuclear energy utilization (passed on 11 January 2000). The regulatory authorities in Ukraine are the Ministry for Ecology and Natural Resources (Nuclear Regulatory Department) and the Ministry of Health (State sanitary-epidemiology supervision). According to the legislation, activities dealing with radiation sources are forbidden without an officially issued permit in Ukraine. Permitted activities with radiation sources are envisaged: licensing of production, storage and maintenance of radiation sources; licensing of the use of radiation sources; obligatory certification of radiation sources and transport

Localization of Simultaneous Moving Sound Sources for Mobile Robot Using a Frequency-Domain Steered Beamformer Approach

OpenAIRE

Valin, Jean-Marc; Michaud, François; Hadjou, Brahim; Rouat, Jean

2016-01-01

Mobile robots in real-life settings would benefit from being able to localize sound sources. Such a capability can nicely complement vision to help localize a person or an interesting event in the environment, and also to provide enhanced processing for other capabilities such as speech recognition. In this paper we present a robust sound source localization method in three-dimensional space using an array of 8 microphones. The method is based on a frequency-domain implementation of a steered...

Extended nonnegative tensor factorisation models for musical sound source separation.

Science.gov (United States)

FitzGerald, Derry; Cranitch, Matt; Coyle, Eugene

2008-01-01

Recently, shift-invariant tensor factorisation algorithms have been proposed for the purposes of sound source separation of pitched musical instruments. However, in practice, existing algorithms require the use of log-frequency spectrograms to allow shift invariance in frequency which causes problems when attempting to resynthesise the separated sources. Further, it is difficult to impose harmonicity constraints on the recovered basis functions. This paper proposes a new additive synthesis-based approach which allows the use of linear-frequency spectrograms as well as imposing strict harmonic constraints, resulting in an improved model. Further, these additional constraints allow the addition of a source filter model to the factorisation framework, and an extended model which is capable of separating mixtures of pitched and percussive instruments simultaneously.

Extended Nonnegative Tensor Factorisation Models for Musical Sound Source Separation

Directory of Open Access Journals (Sweden)

Derry FitzGerald

2008-01-01

Full Text Available Recently, shift-invariant tensor factorisation algorithms have been proposed for the purposes of sound source separation of pitched musical instruments. However, in practice, existing algorithms require the use of log-frequency spectrograms to allow shift invariance in frequency which causes problems when attempting to resynthesise the separated sources. Further, it is difficult to impose harmonicity constraints on the recovered basis functions. This paper proposes a new additive synthesis-based approach which allows the use of linear-frequency spectrograms as well as imposing strict harmonic constraints, resulting in an improved model. Further, these additional constraints allow the addition of a source filter model to the factorisation framework, and an extended model which is capable of separating mixtures of pitched and percussive instruments simultaneously.

Ionizing radiation sources. Ionizing radiation interaction with matter

International Nuclear Information System (INIS)

Popits, R.

1976-01-01

Fundamentals of nuclear physics are reviewed under the headings: obtaining of X-rays and their properties; modes of radioactive decay of natural or man-made radionuclides; radioactive neutron sources; nuclear fission as basis for devising nuclear reactors and weapons; thermonuclear reactions; cosmic radiation. Basic aspects of ionizing radiation interactions with matter are considered with regard to charged particles, photon radiation, and neutrons. (A.B.)

75 FR 19302 - Radiation Sources on Army Land

Science.gov (United States)

2010-04-14

... possession of ionizing radiation sources by non-Army agencies (including their civilian contractors) on an... radiation sources on Army land. The Army requires Non-Army agencies (including their civilian contractors... ionizing radiation sources on an Army Installation. For the purpose of this proposed rule, ``ionizing...

Active sound reduction system and method

NARCIS (Netherlands)

2016-01-01

The present invention refers to an active sound reduction system and method for attenuation of sound emitted by a primary sound source, especially for attenuation of snoring sounds emitted by a human being. This system comprises a primary sound source, at least one speaker as a secondary sound

Radiation Source Replacement Workshop

Energy Technology Data Exchange (ETDEWEB)

Griffin, Jeffrey W.; Moran, Traci L.; Bond, Leonard J.

2010-12-01

This report summarizes a Radiation Source Replacement Workshop in Houston Texas on October 27-28, 2010, which provided a forum for industry and researchers to exchange information and to discuss the issues relating to replacement of AmBe, and potentially other isotope sources used in well logging.

New legislative regulations for ensuring radiation protection using ionizing radiation sources in medicine

International Nuclear Information System (INIS)

Boehm, K.

2018-01-01

European Commission Directive No. 2013/59 / EURATOM laying down basic safety requirements for the provision of radiation protection regulates the provision of radiation protection for workers with radiation sources and residents in all areas of use of ionizing radiation sources. This Directive also addresses radiation protection in the use of ionizing radiation sources in medicine. The European Commission Directive regulates the requirements for radiation protection but also extends to its scope and provisions on the use of medical radiation sources (so-called m edical exposure ) in the scope of further legislation in the field of health care, which has to be amended and modified or possibly issued new. It was necessary in the preparation of the new act on radiation protection to amend simultaneously Act no. 576/2004 on the provision of health care and services related to provision of health care and Act no. 578/2004 on Health care Providers, Health care Professionals and Organizations in Health Care and to prepare a series of implementing regulations not only to the Law on Radiation Protection but also to the Laws governing the Provision of Health Care. The paper presents changes to existing legislation on radiation protection in medical radiation and new requirements for the construction and operation of health workplaces with radiation sources, the protection of the health of patients, the requirements for instrumentation used for medical radiation and radiological instrumentation tests. (authors)

Parameterizing Sound: Design Considerations for an Environmental Sound Database

Science.gov (United States)

2015-04-01

associated with, or produced by, a physical event or human activity and 2) sound sources that are common in the environment. Reproductions or sound...Rogers S. Confrontation naming of environmental sounds. Journal of Clinical and Experimental Neuropsychology . 2000;22(6):830–864. 14 VanDerveer NJ

Design and Calibration Tests of an Active Sound Intensity Probe

Directory of Open Access Journals (Sweden)

Thomas Kletschkowski

2008-01-01

Full Text Available The paper presents an active sound intensity probe that can be used for sound source localization in standing wave fields. The probe consists of a sound hard tube that is terminated by a loudspeaker and an integrated pair of microphones. The microphones are used to decompose the standing wave field inside the tube into its incident and reflected part. The latter is cancelled by an adaptive controller that calculates proper driving signals for the loudspeaker. If the open end of the actively controlled tube is placed close to a vibrating surface, the radiated sound intensity can be determined by measuring the cross spectral density between the two microphones. A one-dimensional free field can be realized effectively, as first experiments performed on a simplified test bed have shown. Further tests proved that a prototype of the novel sound intensity probe can be calibrated.

Effects of Freestream Turbulence on Cavity Tone and Sound Source

Directory of Open Access Journals (Sweden)

Hiroshi Yokoyama

2016-01-01

Full Text Available To clarify the effects of freestream turbulence on cavity tones, flow and acoustic fields were directly predicted for cavity flows with various intensities of freestream turbulence. The freestream Mach number was 0.09 and the Reynolds number based on the cavity length was 4.0 × 104. The depth-to-length ratio of the cavity, D/L, was 0.5 and 2.5, where the acoustic resonance of a depth-mode occurs for D/L = 2.5. The incoming boundary layer was laminar. The results for the intensity of freestream turbulence of Tu = 2.3% revealed that the reduced level of cavity tones in a cavity flow with acoustic resonance (D/L=2.5 was greater than that without acoustic resonance (D/L=0.5. To clarify the reason for this, the sound source based on Lighthill’s acoustic analogy was computed, and the contributions of the intensity and spanwise coherence of the sound source to the reduction of the cavity tone were estimated. As a result, the effects of the reduction of spanwise coherence on the cavity tone were greater in the cavity flow with acoustic resonance than in that without resonance, while the effects of the intensity were comparable for both flows.

Radiation attenuation gauge with magnetically coupled source

International Nuclear Information System (INIS)

Wallace, S.A.

1978-01-01

Disclosed is a radiation attenuation gauge for measuring thickness and density of a material which includes, in combination, a source of gamma radiation contained within a housing of magnetic or ferromagnetic material, and a means for measuring the intensity of gamma radiation. The measuring means has an aperture and magnetic means disposed adjacent to the aperture for attracting and holding the housed source in position before the aperture. The material to be measured is placed between the source and the measuring means

Ionization detector with improved radiation source

International Nuclear Information System (INIS)

Solomon, E.F.

1977-01-01

The detector comprises a chamber having at least one radiation source disposed therein. The chamber includes spaced collector plates which form a part of a detection circuit for sensing changes in the ionization current in the chamber. The radiation source in one embodiment is in the form of a wound wire or ribbon suitably supported in the chamber and preferably a source of beta particles. The chamber may also include an adjustable electrode and the source may function as an adjustable current source by forming the wire or ribbon in an eliptical shape and rotating the structure. In another embodiment the source has a random shape and is homogeneously disposed in the chamber. 13 claims, 5 drawing figures

Olfaction and Hearing Based Mobile Robot Navigation for Odor/Sound Source Search

Science.gov (United States)

Song, Kai; Liu, Qi; Wang, Qi

2011-01-01

Bionic technology provides a new elicitation for mobile robot navigation since it explores the way to imitate biological senses. In the present study, the challenging problem was how to fuse different biological senses and guide distributed robots to cooperate with each other for target searching. This paper integrates smell, hearing and touch to design an odor/sound tracking multi-robot system. The olfactory robot tracks the chemical odor plume step by step through information fusion from gas sensors and airflow sensors, while two hearing robots localize the sound source by time delay estimation (TDE) and the geometrical position of microphone array. Furthermore, this paper presents a heading direction based mobile robot navigation algorithm, by which the robot can automatically and stably adjust its velocity and direction according to the deviation between the current heading direction measured by magnetoresistive sensor and the expected heading direction acquired through the odor/sound localization strategies. Simultaneously, one robot can communicate with the other robots via a wireless sensor network (WSN). Experimental results show that the olfactory robot can pinpoint the odor source within the distance of 2 m, while two hearing robots can quickly localize and track the olfactory robot in 2 min. The devised multi-robot system can achieve target search with a considerable success ratio and high stability. PMID:22319401

Olfaction and Hearing Based Mobile Robot Navigation for Odor/Sound Source Search

Directory of Open Access Journals (Sweden)

Qi Wang

2011-02-01

Full Text Available Bionic technology provides a new elicitation for mobile robot navigation since it explores the way to imitate biological senses. In the present study, the challenging problem was how to fuse different biological senses and guide distributed robots to cooperate with each other for target searching. This paper integrates smell, hearing and touch to design an odor/sound tracking multi-robot system. The olfactory robot tracks the chemical odor plume step by step through information fusion from gas sensors and airflow sensors, while two hearing robots localize the sound source by time delay estimation (TDE and the geometrical position of microphone array. Furthermore, this paper presents a heading direction based mobile robot navigation algorithm, by which the robot can automatically and stably adjust its velocity and direction according to the deviation between the current heading direction measured by magnetoresistive sensor and the expected heading direction acquired through the odor/sound localization strategies. Simultaneously, one robot can communicate with the other robots via a wireless sensor network (WSN. Experimental results show that the olfactory robot can pinpoint the odor source within the distance of 2 m, while two hearing robots can quickly localize and track the olfactory robot in 2 min. The devised multi-robot system can achieve target search with a considerable success ratio and high stability.

Competing sound sources reveal spatial effects in cortical processing.

Directory of Open Access Journals (Sweden)

Ross K Maddox

Full Text Available Why is spatial tuning in auditory cortex weak, even though location is important to object recognition in natural settings? This question continues to vex neuroscientists focused on linking physiological results to auditory perception. Here we show that the spatial locations of simultaneous, competing sound sources dramatically influence how well neural spike trains recorded from the zebra finch field L (an analog of mammalian primary auditory cortex encode source identity. We find that the location of a birdsong played in quiet has little effect on the fidelity of the neural encoding of the song. However, when the song is presented along with a masker, spatial effects are pronounced. For each spatial configuration, a subset of neurons encodes song identity more robustly than others. As a result, competing sources from different locations dominate responses of different neural subpopulations, helping to separate neural responses into independent representations. These results help elucidate how cortical processing exploits spatial information to provide a substrate for selective spatial auditory attention.

Evolution of Sound Source Localization Circuits in the Nonmammalian Vertebrate Brainstem

DEFF Research Database (Denmark)

Walton, Peggy L; Christensen-Dalsgaard, Jakob; Carr, Catherine E

2017-01-01

The earliest vertebrate ears likely subserved a gravistatic function for orientation in the aquatic environment. However, in addition to detecting acceleration created by the animal's own movements, the otolithic end organs that detect linear acceleration would have responded to particle movement...... to increased sensitivity to a broader frequency range and to modification of the preexisting circuitry for sound source localization....

Movement and Perceptual Strategies to Intercept Virtual Sound Sources.

Directory of Open Access Journals (Sweden)

Naeem eKomeilipoor

2015-05-01

Full Text Available To intercept a moving object, one needs to be in the right place at the right time. In order to do this, it is necessary to pick up and use perceptual information that specifies the time to arrival of an object at an interception point. In the present study, we examined the ability to intercept a laterally moving virtual sound object by controlling the displacement of a sliding handle and tested whether and how the interaural time difference (ITD could be the main source of perceptual information for successfully intercepting the virtual object. The results revealed that in order to accomplish the task, one might need to vary the duration of the movement, control the hand velocity and time to reach the peak velocity (speed coupling, while the adjustment of movement initiation did not facilitate performance. Furthermore, the overall performance was more successful when subjects employed a time-to-contact (tau coupling strategy. This result shows that prospective information is available in sound for guiding goal-directed actions.

Security of radioactive sources in radiation facilities

International Nuclear Information System (INIS)

2011-03-01

Safety codes and safety standards are formulated on the basis of internationally accepted safety criteria for design, construction and operation of specific equipment, systems, structures and components of nuclear and radiation facilities. Safety codes establish the objectives and set requirements that shall be fulfilled to provide adequate assurance for safety. Safety guides and guidelines elaborate various requirements and furnish approaches for their implementation. Safety manuals deal with specific topics and contain detailed scientific and technical information on the subject. These documents are prepared by experts in the relevant fields and are extensively reviewed by advisory committees of the Board before they are published. The documents are revised when necessary, in the light of experience and feedback from users as well as new developments in the field. In India, radiation sources are being widely used for societal benefits in industry, medical practices, research, training and agriculture. It has been reported from all over the world that unsecured radioactive sources caused serious radiological accidents involving radiation injuries and fatalities. Particular concern was expressed regarding radioactive sources that have become orphaned (not under regulatory control) or vulnerable (under weak regulatory control and about to be orphaned). There is a concern about safety and security of radioactive sources and hence the need of stringent regulatory control over the handling of the sources and their security. In view of this, this guide is prepared which gives provisions necessary to safeguard radiation installations against theft of radioactive sources and other malevolent acts that may result in radiological consequences. It is, therefore, required that the radiation sources are used safely and managed securely by only authorised personnel. This guide is intended to be used by users of radiation sources in developing the necessary security plan for

Radiation: Basic life for human

International Nuclear Information System (INIS)

Wan Saffiey Wan Abdullah

2009-01-01

Basically, radiation is sources for everything in this world. From radiation, many reactions and activities can be done by organisms. The tree can do photosynthesis and at the same time can give oxygen to human and others. In Quran, radiation was mentioned almost 41 times and from that, 12 are preferred to sun, moon, and stars. Radiation can be classified into two groups, mechanical and electromagnetic. Mechanical radiations are produced from vibration process. For example, when we are talking, sound radiation will be produced from vibration of sounds box. The guitar will sounded when we pluck it. Generally, mechanical radiation needs medium for its propagation and the velocity of wave can change and it cannot propagate in vacuum states. Meanwhile, electromagnetic radiations are energy that emitted in wave produced by propagation of electrical charges. This will produce magnetic fields and then if these fields changed, electrical fields will produce. There are two types of radiation in human life, natural radiation and artificially radiation. Radiation can be applied in medical and defend sector. Radiation also can be misuse by some people that want it for other purpose in intention to do something wrong, such as in making bomb and others weapons. In Malaysia, there are one act to control the imports, exports, licensing, transferring and application of ionizing radiation but not for non-ionizing radiation. In future, laser radiations have their own potential to become one of the most important radiations in renewable energy sector, medical and defend.

Radiation effects on light sources and detectors

International Nuclear Information System (INIS)

Barnes, C.E.

1985-01-01

The rapidly expanding field of optoelectronics includes a wide variety of both military and non-military applications in which the systems must meet radiation exposure requirements. Herein, we review the work on radiation effects on sources and detectors for such optoelectronic systems. For sources the principal problem is permanent damage-induced light output degradation, while for detectors it is ionizing radiation-induced photocurrents

Kinetic theory for radiation interacting with sound waves in ultrarelativistic pair plasmas

International Nuclear Information System (INIS)

Marklund, Mattias; Shukla, Padma K.; Stenflo, Lennart

2006-01-01

A kinetic theory for radiation interacting with sound waves in an ultrarelativistic electron-positron plasma is developed. It is shown that the effect of a spatial spectral broadening of the electromagnetic pulse is to introduce a reduction of the growth rates for the decay and modulational instabilities. Such spectral broadening could be due to a finite pulse coherence length, or through the use of random phase filters, and would stabilize the propagation of electromagnetic pulses

Natural radiation sources fabricated from potassic chemical fertilizers and application to radiation education

International Nuclear Information System (INIS)

Kawano, Takao

2010-01-01

Potassic chemical fertilizers contain potassium, a small part of which is potassium-40. Since potassium-40 is a naturally occurring radioisotope, potassic chemical fertilizers are often used for demonstrations of the existence of natural radioisotopes and radiation. To fabricate radiation sources as educational tools, the compression and formation method developed by our previous study was applied to 13 brands of commercially available chemical fertilizers containing different amounts of potassium. The suitability (size, weight, and solidness) of thus fabricated sources was examined and 12 of them were selected as easy-to-use radiation sources at radiation educational courses. The radiation strength (radiation count rate measured by a GM survey meter) and potassium content of the 12 sources were examined. It was found that the count rate was wholly proportional to the percentage of potassium, and a new educational application was proposed and discussed for understanding that the substance emitting radiation must be the potassium present in the raw fertilizers. (author)

Separation of radiation from two sources from their known radiated sum field

DEFF Research Database (Denmark)

Laitinen, Tommi; Pivnenko, Sergey

2011-01-01

This paper presents a technique for complete and exact separation of the radiated fields of two sources (at the same frequency) from the knowledge of their radiated sum field. The two sources can be arbitrary but it must be possible to enclose the sources inside their own non-intersecting minimum...

Efficient techniques for wave-based sound propagation in interactive applications

Science.gov (United States)

Mehra, Ravish

Sound propagation techniques model the effect of the environment on sound waves and predict their behavior from point of emission at the source to the final point of arrival at the listener. Sound is a pressure wave produced by mechanical vibration of a surface that propagates through a medium such as air or water, and the problem of sound propagation can be formulated mathematically as a second-order partial differential equation called the wave equation. Accurate techniques based on solving the wave equation, also called the wave-based techniques, are too expensive computationally and memory-wise. Therefore, these techniques face many challenges in terms of their applicability in interactive applications including sound propagation in large environments, time-varying source and listener directivity, and high simulation cost for mid-frequencies. In this dissertation, we propose a set of efficient wave-based sound propagation techniques that solve these three challenges and enable the use of wave-based sound propagation in interactive applications. Firstly, we propose a novel equivalent source technique for interactive wave-based sound propagation in large scenes spanning hundreds of meters. It is based on the equivalent source theory used for solving radiation and scattering problems in acoustics and electromagnetics. Instead of using a volumetric or surface-based approach, this technique takes an object-centric approach to sound propagation. The proposed equivalent source technique generates realistic acoustic effects and takes orders of magnitude less runtime memory compared to prior wave-based techniques. Secondly, we present an efficient framework for handling time-varying source and listener directivity for interactive wave-based sound propagation. The source directivity is represented as a linear combination of elementary spherical harmonic sources. This spherical harmonic-based representation of source directivity can support analytical, data

Regulated control of practices and radiation sources

International Nuclear Information System (INIS)

1992-01-01

Excepting the radiation caused by the natural background radiation, the Executive Secretariat for Nuclear Affairs (SEAN) does not authorize any source no practice within the national territory that may imply exposure of a person to ionizing radiation unless this use is ruled. This document establishes the basic criteria to set up such system as well as to exclude or exempt practices and sources from this regulated control

Sound Source Localization through 8 MEMS Microphones Array Using a Sand-Scorpion-Inspired Spiking Neural Network.

Science.gov (United States)

Beck, Christoph; Garreau, Guillaume; Georgiou, Julius

2016-01-01

Sand-scorpions and many other arachnids perceive their environment by using their feet to sense ground waves. They are able to determine amplitudes the size of an atom and locate the acoustic stimuli with an accuracy of within 13° based on their neuronal anatomy. We present here a prototype sound source localization system, inspired from this impressive performance. The system presented utilizes custom-built hardware with eight MEMS microphones, one for each foot, to acquire the acoustic scene, and a spiking neural model to localize the sound source. The current implementation shows smaller localization error than those observed in nature.

Future Synchrotron Radiation Sources

CERN Document Server

Winick, Herman

2003-01-01

Sources of synchrotron radiation (also called synchrotron light) and their associated research facilities have experienced a spectacular growth in number, performance, and breadth of application in the past two to three decades. In 1978 there were eleven electron storage rings used as light sources. Three of these were small rings, all below 500 mega-electron volts (MeV), dedicated to this purpose; the others, with energy up to 5 giga-electron volts (GeV), were used parasitically during the operation of the ring for high energy physics research. In addition, at that time synchrotron radiation from nine cyclic electron synchrotrons, with energy up to 5 GeV, was also used parasitically. At present no cyclic synchrotrons are used, while about 50 electron storage rings are in operation around the world as fully dedicated light sources for basic and applied research in a wide variety of fields. Among these fields are structural molecular biology, molecular environmental science, materials, analytic chemistry, micr...

Radiation sources and methods for producing them

International Nuclear Information System (INIS)

Malson, H.A.; Moyer, S.E.; Honious, H.B.; Janzow, E.F.

1979-01-01

The radiation sources contain a substrate with an electrically conducting, non-radioactive metal surface, a layer of a metal isotope of the scandium group as well as a percentage of non-radioactive binding metal being coated on the surface by means of an electroplating method. Besides examples for β sources ( 147 Pm), γ sources ( 241 Am), and neutron sources ( 252 Cf) there is described an α-radiation source ( 241 Am, 244 Cu, 238 Pu) for smoke detectors. There are given extensive tables and a bibliography. (DG) [de

X radiation sources based on accelerators

International Nuclear Information System (INIS)

Couprie, M.E.; Filhol, J.M.

2008-01-01

Light sources based on accelerators aim at producing very high brilliance coherent radiation, tunable from the infrared to X-ray range, with picosecond or femtosecond light pulses. The first synchrotron light sources were built around storage rings in which a large number of relativistic electrons produce 'synchrotron radiation' when their trajectory is subjected to a magnetic field, either in bending magnets or in specific insertion devices (undulators), made of an alternating series of magnets, allowing the number of curvatures to be increased and the radiation to be reinforced. These 'synchrotron radiation' storage rings are now used worldwide (there are more than thirty), and they simultaneously distribute their radiation to several tens of users around the storage ring. The most effective installations in term of brilliance are the so-called third generation synchrotron radiation light sources. The radiation produced presents pulse durations of the order of a few tens of ps, at a high rate (of the order of MHz); it is tunable over a large range, depending on the magnetic field and the electron beam energy and its polarisation is adjustable (in the V-UV-soft-X range). Generally, a very precise spectral selection is made by the users with a monochromator. The single pass linear accelerators can produce very short electron bunches (around 100 fs). The beam of very high electronic density is sent into successive undulator modules, reinforcing the radiation's longitudinal coherence, produced according to a Free Electron Laser (FEL) scheme by the interaction between the electron bunch and a light wave. The very high peak brilliance justifies their designation as fourth generation sources. The number of users is smaller because an electron pulse produces a radiation burst towards only one beamline. Energy Recovery Linacs (ERL) let the beam pass several times in the accelerator structures either to recover the energy or to accelerate the electrons during several turns

Radiation therapy sources, equipment and installations

International Nuclear Information System (INIS)

2011-03-01

The safety code for Telegamma Therapy Equipment and Installations, (AERB/SC/MED-1) and safety code for Brachytherapy Sources, Equipment and Installations, (AERB/SC/MED-3) were issued by AERB in 1986 and 1988 respectively. These codes specified mandatory requirements for radiation therapy facilities, covering the entire spectrum of operations ranging from the setting up of a facility to its ultimate decommissioning, including procedures to be followed during emergency situations. The codes also stipulated requirements of personnel and their responsibilities. With the advent of new techniques and equipment such as 3D-conformal radiation therapy, intensity modulated radiation therapy, image guided radiation therapy, treatment planning system, stereotactic radiosurgery, stereotactic radiotherapy, portal imaging, integrated brachytherapy and endovascular brachytherapy during the last two decades, AERB desires that these codes be revised and merged into a single code titled Radiation Therapy Sources, Equipment, and Installations

On the relevance of source effects in geomagnetic pulsations for induction soundings

Science.gov (United States)

Neska, Anne; Tadeusz Reda, Jan; Leszek Neska, Mariusz; Petrovich Sumaruk, Yuri

2018-03-01

This study is an attempt to close a gap between recent research on geomagnetic pulsations and their usage as source signals in electromagnetic induction soundings (i.e., magnetotellurics, geomagnetic depth sounding, and magnetovariational sounding). The plane-wave assumption as a precondition for the proper performance of these methods is partly violated by the local nature of field line resonances which cause a considerable portion of pulsations at mid latitudes. It is demonstrated that and explained why in spite of this, the application of remote reference stations in quasi-global distances for the suppression of local correlated-noise effects in induction arrows is possible in the geomagnetic pulsation range. The important role of upstream waves and of the magnetic equatorial region for such applications is emphasized. Furthermore, the principal difference between application of reference stations for local transfer functions (which result in sounding curves and induction arrows) and for inter-station transfer functions is considered. The preconditions for the latter are much stricter than for the former. Hence a failure to estimate an inter-station transfer function to be interpreted in terms of electromagnetic induction, e.g., because of field line resonances, does not necessarily prohibit use of the station pair for a remote reference estimation of the impedance tensor.

On the relevance of source effects in geomagnetic pulsations for induction soundings

Directory of Open Access Journals (Sweden)

A. Neska

2018-03-01

Full Text Available This study is an attempt to close a gap between recent research on geomagnetic pulsations and their usage as source signals in electromagnetic induction soundings (i.e., magnetotellurics, geomagnetic depth sounding, and magnetovariational sounding. The plane-wave assumption as a precondition for the proper performance of these methods is partly violated by the local nature of field line resonances which cause a considerable portion of pulsations at mid latitudes. It is demonstrated that and explained why in spite of this, the application of remote reference stations in quasi-global distances for the suppression of local correlated-noise effects in induction arrows is possible in the geomagnetic pulsation range. The important role of upstream waves and of the magnetic equatorial region for such applications is emphasized. Furthermore, the principal difference between application of reference stations for local transfer functions (which result in sounding curves and induction arrows and for inter-station transfer functions is considered. The preconditions for the latter are much stricter than for the former. Hence a failure to estimate an inter-station transfer function to be interpreted in terms of electromagnetic induction, e.g., because of field line resonances, does not necessarily prohibit use of the station pair for a remote reference estimation of the impedance tensor.

Incidents with hazardous radiation sources; Zwischenfaelle mit gefaehrlichen Strahlenquellen

Energy Technology Data Exchange (ETDEWEB)

Schoenhacker, Stefan [Bundesministerium fuer Inneres, Traiskirchen (Austria). Abt. 1/9 - Zivilschutzschule

2016-07-01

Incidents with hazardous radiation sources can occur in any country, even those without nuclear facilities. Preparedness for such incidents is supposed to fulfill globally agreed minimum standards. Incidents are categorized in incidents with licensed handling of radiation sources as for material testing, transport accidents of hazardous radiation sources, incidents with radionuclide batteries, incidents with satellites containing radioactive inventory, incidents wit not licensed handling of illegally acquired hazardous radiation sources. The emergency planning in Austria includes a differentiation according to the consequences: incidents with release of radioactive materials resulting in restricted contamination, incidents with release of radioactive materials resulting in local contamination, and incidents with the hazard of e@nhanced exposure due to the radiation source.

Training in radiation protection and the safe use of radiation sources

International Nuclear Information System (INIS)

2001-01-01

The need for education and training in the various disciplines of radiation protection has long been recognized by the IAEA, the International Labour Organization (ILO), the United Nations Educational, Scientific and Cultural Organization, the World Health Organization and the Pan American Health Organization (PAHO). This need has been partially met through the many training courses undertaken by these organizations, either individually or in collaboration. The IAEA has assisted developing Member States in the training of specialists in radiation protection and safety through its organized educational and specialized training courses, workshops, seminars, fellowships and scientific visits. Training is an important means of promoting safety culture and enhancing the level of competence of personnel involved in radiation protection activities, and has acquired a place in the IAEA's programme accordingly. For example, the IAEA Post-graduate Educational Course in Radiation Protection and the Safe Use of Radiation Sources is regularly offered in countries around the world, and has been provided in Arabic, English, French, Spanish and Russian. The training provided by the IAEA is primarily aimed at regulators, professionals working in radiation protection and those responsible for the development of training programmes in their own countries. The importance of adequate and appropriate training for all those working with ionizing radiation has been highlighted by the results of the IAEA's investigations of radiological accidents. A significant contributory factor in a number of the accidents has been a lack of adequate training, which gave rise to errors with serious consequences. This report provides assistance in organizing training and complying with the requirements on training of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS). The previous version of this report. Technical Reports

Regulatory aspects of radiation sources safety in Albania

International Nuclear Information System (INIS)

Dollani, K.; Kushe, R.

1998-01-01

In this paper are presented the regulatory aspects of the radiation sources safety in Albania, based in the new Radiological Protection Act and Regulations. The radiation protection infrastructures and procedures are described as well as their functioning for the implementation of relevant activities such as licensing and regular inspection, personal dose monitoring, emergency preparedness which are developed in the frame of the IAEA Technical Co-operation Programme. The issue of the security of radiation sources is dealt in close relation with the preparation and use of the inventory of all radiation sources in the country. A special attention is paid to the identification and location of lost sources for their finding and secure storage. (author)

Indirect detection of radiation sources through direct detection of radiolysis products

Science.gov (United States)

Farmer, Joseph C [Tracy, CA; Fischer, Larry E [Los Gatos, CA; Felter, Thomas E [Livermore, CA

2010-04-20

A system for indirectly detecting a radiation source by directly detecting radiolytic products. The radiation source emits radiation and the radiation produces the radiolytic products. A fluid is positioned to receive the radiation from the radiation source. When the fluid is irradiated, radiolytic products are produced. By directly detecting the radiolytic products, the radiation source is detected.

Synchrotron radiation sources: general features and vacuum system

International Nuclear Information System (INIS)

Craievich, A.F.

1985-01-01

In the last years the electron or positron storage rings, which were until 1970 only used for high energy physics experiments, begun to be built in several countries exclusively as electromagnetic radiation source (synchrotron radiation). The sources are generally made up by injector (linear accelerator or microtron), 'booster' (synchrotron), storage ring, insertions ('Wigglers' and ondulators) and light lines. The interest by these sources are due to the high intensity, large spectrum (from infrared to the X-rays), polarization and pulsed structure of the produced radiation. For the ultra-vacuum obtainement, necessary for the functioning storage rings (p=10 -9 Torr), several special procedures are used. In Brazil the Synchrotron Radiation National Laboratory of the CNPq worked out a conceptual project of synchrotron radiation source, whose execution should begin by the construction of the several components prototypes. (L.C.) [pt

Estimates of radiation doses from various sources of exposure

International Nuclear Information System (INIS)

Anon.

1992-01-01

This chapter provides an overview of radiation doses to individuals and to the collective US population from various sources of ionizing radiation. Summary tables present doses from various sources of ionizing radiation. Summary tables present doses from occupational exposures and annual per capita doses from natural background, the healing arts, nuclear weapons, nuclear energy and consumer products. Although doses from non-ionizing radiation are not as yet readily available in a concise form, the major sources of non-ionizing radiation are listed

A location procedure for sound sources in reactor-technical enclosures

International Nuclear Information System (INIS)

Hamann, D.

1982-07-01

A passive method requiring one detector only has been developed for the location of sound emitting faults in nuclear power plant components. It is adapted for use in a frequency range the wavelength of which is of the same order of magnitude as characteristic dimensions of the considered enclosure. The location is performed in the following way: (1) For a fixed detector position the Auto Power Spectral Density (APSD) of the source to be located is measured. (2) For this detector position the APSD is calculated for the potential source locations. For this, the free-field APSD as well as the acoustic normal modes of the enclosure are necessary. (3) The measured APSD is compared with the theoretically obtained APSD's. (4) That APSD is determined which is most similar to the measured APSD, and consequently an information about the unknown source position is got. (author)

The effect of sound speed profile on shallow water shipping sound maps

NARCIS (Netherlands)

Sertlek, H.Ö.; Binnerts, B.; Ainslie, M.A.

2016-01-01

Sound mapping over large areas can be computationally expensive because of the large number of sources and large source-receiver separations involved. In order to facilitate computation, a simplifying assumption sometimes made is to neglect the sound speed gradient in shallow water. The accuracy of

Plasma x-ray radiation source.

Science.gov (United States)

Popkov, N F; Kargin, V I; Ryaslov, E A; Pikar', A S

1995-01-01

This paper gives the results of studies on a plasma x-ray source, which enables one to obtain a 2.5-krad radiation dose per pulse over an area of 100 cm2 in the quantum energy range from 20 to 500 keV. Pulse duration is 100 ns. Spectral radiation distributions from a diode under various operation conditions of a plasma are obtained. A Marx generator served as an initial energy source of 120 kJ with a discharge time of T/4 = 10-6 s. A short electromagnetic pulse (10-7 s) was shaped using plasma erosion opening switches.

Sound Source Localization Through 8 MEMS Microphones Array Using a Sand-Scorpion-Inspired Spiking Neural Network

Directory of Open Access Journals (Sweden)

Christoph Beck

2016-10-01

Full Text Available Sand-scorpions and many other arachnids perceive their environment by using their feet to sense ground waves. They are able to determine amplitudes the size of an atom and locate the acoustic stimuli with an accuracy of within 13° based on their neuronal anatomy. We present here a prototype sound source localization system, inspired from this impressive performance. The system presented utilizes custom-built hardware with eight MEMS microphones, one for each foot, to acquire the acoustic scene, and a spiking neural model to localize the sound source. The current implementation shows smaller localization error than those observed in nature.

Second harmonic sound field after insertion of a biological tissue sample

Science.gov (United States)

Zhang, Dong; Gong, Xiu-Fen; Zhang, Bo

2002-01-01

Second harmonic sound field after inserting a biological tissue sample is investigated by theory and experiment. The sample is inserted perpendicular to the sound axis, whose acoustical properties are different from those of surrounding medium (distilled water). By using the superposition of Gaussian beams and the KZK equation in quasilinear and parabolic approximations, the second harmonic field after insertion of the sample can be derived analytically and expressed as a linear combination of self- and cross-interaction of the Gaussian beams. Egg white, egg yolk, porcine liver, and porcine fat are used as the samples and inserted in the sound field radiated from a 2 MHz uniformly excited focusing source. Axial normalized sound pressure curves of the second harmonic wave before and after inserting the sample are measured and compared with the theoretical results calculated with 10 items of Gaussian beam functions.

Ionizing radiations: effects and sources

International Nuclear Information System (INIS)

Vignes, S.; Nenot, J.C.

1978-01-01

Having first mentioned the effects of ionizing radiations in cancerogenisis, pre-natal, and genetic fields, the authors present the different sources of radiations and estimate their respective contributions to the total irradiation dose. Their paper makes reference to the main elements of a report issued by the United Nations Scientific Committee in 1977 [fr

Sound source measurement by using a passive sound insulation and a statistical approach

Science.gov (United States)

Dragonetti, Raffaele; Di Filippo, Sabato; Mercogliano, Francesco; Romano, Rosario A.

2015-10-01

This paper describes a measurement technique developed by the authors that allows carrying out acoustic measurements inside noisy environments reducing background noise effects. The proposed method is based on the integration of a traditional passive noise insulation system with a statistical approach. The latter is applied to signals picked up by usual sensors (microphones and accelerometers) equipping the passive sound insulation system. The statistical approach allows improving of the sound insulation given only by the passive sound insulation system at low frequency. The developed measurement technique has been validated by means of numerical simulations and measurements carried out inside a real noisy environment. For the case-studies here reported, an average improvement of about 10 dB has been obtained in a frequency range up to about 250 Hz. Considerations on the lower sound pressure level that can be measured by applying the proposed method and the measurement error related to its application are reported as well.

The safety of radiation sources and radioactive materials in China

International Nuclear Information System (INIS)

Liu, H.

2001-01-01

The report describes the present infrastructure for the safety of radiation sources in China, where applications of radiation sources have become more and more widespread in the past years. In particular, it refers to the main functions of the National Nuclear Safety Administration of the State Environmental Protection Administration (SEPA), which is acting as the regulatory body for nuclear and radiation safety at nuclear installations, the Ministry of Public Health which issues licences for the use of radiation sources, and the Ministry of Public Security, which deals with the security of radiation sources. The report also refers to the main requirements of the existing regulatory system for radiation safety, i.e. the basic dose limits for radiation workers and the public, the licensing system for nuclear installations and for radioisotope-based and other irradiation devices, and the environmental impact assessment system. Information on the nationwide survey of radiation sources carried out by SEPA in 1991 is provided, and on some accidents that occurred in China due to loss of control of radiation sources and errors in the operation of irradiation facilities. (author)

Low frequency interference between short synchrotron radiation sources

Directory of Open Access Journals (Sweden)

F. Méot

2001-06-01

Full Text Available A recently developed analytical formalism describing low frequency far-field synchrotron radiation (SR is applied to the calculation of spectral angular radiation densities from interfering short sources (edge, short magnet. This is illustrated by analytical calculation of synchrotron radiation from various assemblies of short dipoles, including an “isolated” highest density infrared SR source.

Perception by Operators of Approach and Withdrawal of Moving Sound Sources

Science.gov (United States)

1999-01-01

Tucker, 1988; Strybel and Neal, 1994) or between stationary and moving sound sources or auditory images (Perrott and Musikant , 1977; Strybel and Neale...conditions of stimulation (Viskov, 1975; Perrott and Musikant , 1977; Strybel et al., 1989; Sabery and Perrott, 1990; Strybel et al., 1992; Strybel and...noise and its relation to masking and loudness// JASA, 1947. V.19. P. 609-619. 24. Perrott D.R., Musicant A.D. Minimum auditory movement angle: binaural

[Use of ionizing radiation sources in metallurgy: risk assessment].

Science.gov (United States)

Giugni, U

2012-01-01

Use of ionizing radiation sources in the metallurgical industry: risk assessment. Radioactive sources and fixed or mobile X-ray equipment are used for both process and quality control. The use of ionizing radiation sources requires careful risk assessment. The text lists the characteristics of the sources and the legal requirements, and contains a description of the documentation required and the methods used for risk assessment. It describes how to estimate the doses to operators and the relevant classification criteria used for the purpose of radiation protection. Training programs must be organized in close collaboration between the radiation protection expert and the occupational physician.

Identification of impact force acting on composite laminated plates using the radiated sound measured with microphones

Science.gov (United States)

Atobe, Satoshi; Nonami, Shunsuke; Hu, Ning; Fukunaga, Hisao

2017-09-01

Foreign object impact events are serious threats to composite laminates because impact damage leads to significant degradation of the mechanical properties of the structure. Identification of the location and force history of the impact that was applied to the structure can provide useful information for assessing the structural integrity. This study proposes a method for identifying impact forces acting on CFRP (carbon fiber reinforced plastic) laminated plates on the basis of the sound radiated from the impacted structure. Identification of the impact location and force history is performed using the sound pressure measured with microphones. To devise a method for identifying the impact location from the difference in the arrival times of the sound wave detected with the microphones, the propagation path of the sound wave from the impacted point to the sensor is examined. For the identification of the force history, an experimentally constructed transfer matrix is employed to relate the force history to the corresponding sound pressure. To verify the validity of the proposed method, impact tests are conducted by using a CFRP cross-ply laminate as the specimen, and an impulse hammer as the impactor. The experimental results confirm the validity of the present method for identifying the impact location from the arrival time of the sound wave detected with the microphones. Moreover, the results of force history identification show the feasibility of identifying the force history accurately from the measured sound pressure using the experimental transfer matrix.

Guidelines for testing sealed radiation sources

International Nuclear Information System (INIS)

1989-01-01

These guidelines are based on article 16(1) of the Ordinance on the Implementation of Atomic Safety and Radiation Protection dated 11 October 1984 (VOAS), in connection with article 36 of the Executory Provision to the VOAS, of 11 October 1984. They apply to the testing of sealed sources to verify their intactness, tightness and non-contamination as well as observance of their fixed service time. The type, scope and intervals of testing as well as the evaluation of test results are determined. These guidelines also apply to the testing of radiation sources forming part of radiation equipment, unless otherwise provided for in the type license or permit. These guidelines enter into force on 1 January 1990

Performance of an open-source heart sound segmentation algorithm on eight independent databases.

Science.gov (United States)

Liu, Chengyu; Springer, David; Clifford, Gari D

2017-08-01

Heart sound segmentation is a prerequisite step for the automatic analysis of heart sound signals, facilitating the subsequent identification and classification of pathological events. Recently, hidden Markov model-based algorithms have received increased interest due to their robustness in processing noisy recordings. In this study we aim to evaluate the performance of the recently published logistic regression based hidden semi-Markov model (HSMM) heart sound segmentation method, by using a wider variety of independently acquired data of varying quality. Firstly, we constructed a systematic evaluation scheme based on a new collection of heart sound databases, which we assembled for the PhysioNet/CinC Challenge 2016. This collection includes a total of more than 120 000 s of heart sounds recorded from 1297 subjects (including both healthy subjects and cardiovascular patients) and comprises eight independent heart sound databases sourced from multiple independent research groups around the world. Then, the HSMM-based segmentation method was evaluated using the assembled eight databases. The common evaluation metrics of sensitivity, specificity, accuracy, as well as the [Formula: see text] measure were used. In addition, the effect of varying the tolerance window for determining a correct segmentation was evaluated. The results confirm the high accuracy of the HSMM-based algorithm on a separate test dataset comprised of 102 306 heart sounds. An average [Formula: see text] score of 98.5% for segmenting S1 and systole intervals and 97.2% for segmenting S2 and diastole intervals were observed. The [Formula: see text] score was shown to increases with an increases in the tolerance window size, as expected. The high segmentation accuracy of the HSMM-based algorithm on a large database confirmed the algorithm's effectiveness. The described evaluation framework, combined with the largest collection of open access heart sound data, provides essential resources for

A "looming bias" in spatial hearing? Effects of acoustic intensity and spectrum on categorical sound source localization.

Science.gov (United States)

McCarthy, Lisa; Olsen, Kirk N

2017-01-01

Continuous increases of acoustic intensity (up-ramps) can indicate a looming (approaching) sound source in the environment, whereas continuous decreases of intensity (down-ramps) can indicate a receding sound source. From psychoacoustic experiments, an "adaptive perceptual bias" for up-ramp looming tonal stimuli has been proposed (Neuhoff, 1998). This theory postulates that (1) up-ramps are perceptually salient because of their association with looming and potentially threatening stimuli in the environment; (2) tonal stimuli are perceptually salient because of an association with single and potentially threatening biological sound sources in the environment, relative to white noise, which is more likely to arise from dispersed signals and nonthreatening/nonbiological sources (wind/ocean). In the present study, we extrapolated the "adaptive perceptual bias" theory and investigated its assumptions by measuring sound source localization in response to acoustic stimuli presented in azimuth to imply looming, stationary, and receding motion in depth. Participants (N = 26) heard three directions of intensity change (up-ramps, down-ramps, and steady state, associated with looming, receding, and stationary motion, respectively) and three levels of acoustic spectrum (a 1-kHz pure tone, the tonal vowel /ә/, and white noise) in a within-subjects design. We first hypothesized that if up-ramps are "perceptually salient" and capable of eliciting adaptive responses, then they would be localized faster and more accurately than down-ramps. This hypothesis was supported. However, the results did not support the second hypothesis. Rather, the white-noise and vowel conditions were localized faster and more accurately than the pure-tone conditions. These results are discussed in the context of auditory and visual theories of motion perception, auditory attentional capture, and the spectral causes of spatial ambiguity.

Methods to identify and locate spent radiation sources

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

The objective of this manual is to provide essential guidance to Member States with nuclear applications involving the use of a wide range of sealed radiation sources on the practical task of physically locating spent radiation sources not properly accounted for. Advice is also provided to render the located source safe on location. Refs, figs and tabs.

Methods to identify and locate spent radiation sources

International Nuclear Information System (INIS)

1997-06-01

The objective of this manual is to provide essential guidance to Member States with nuclear applications involving the use of a wide range of sealed radiation sources on the practical task of physically locating spent radiation sources not properly accounted for. Advice is also provided to render the located source safe on location. Refs, figs, tabs

Methods to identify and locate spent radiation sources

International Nuclear Information System (INIS)

1995-07-01

The objective of this manual is to provide essential guidance to Member States with nuclear applications involving the use of a wide range of sealed radiation sources on the practical task of physically locating spent radiation sources not properly accounted for. Advice is also provided to render the located source safe on location. Refs, figs and tabs

On the sound absorption coefficient of porous asphalt pavements for oblique incident sound waves

NARCIS (Netherlands)

Bezemer-Krijnen, Marieke; Wijnant, Ysbrand H.; de Boer, Andries; Bekke, Dirk; Davy, J.; Don, Ch.; McMinn, T.; Dowsett, L.; Broner, N.; Burgess, M.

2014-01-01

A rolling tyre will radiate noise in all directions. However, conventional measurement techniques for the sound absorption of surfaces only give the absorption coefficient for normal incidence. In this paper, a measurement technique is described with which it is possible to perform in situ sound

Nature and magnitude of the problem of spent radiation sources

International Nuclear Information System (INIS)

1991-09-01

Various types of sealed radiation sources are widely used in industry, medicine and research. Virtually all countries have some sealed sources. The activity in the sources varies from kilobecquerels in consumer products to hundreds of pentabecquerels in facilities for food irradiation. Loss or misuse of sealed sources can give rise to accidents resulting in radiation exposure of workers and members of the general public, and can also give rise to extensive contamination of land, equipment and buildings. In extreme cases the exposure can be lethal. Problems of safety relating to spent radiation sources have been under consideration within the Agency for some years. The first objective of the project has been to prepare a comprehensive report reviewing the nature and background of the problem, also giving an overview of existing practices for the management of spent radiation sources. This report is the fulfilment of this first objective. The safe management of spent radiation sources cannot be studied in isolation from their normal use, so it has been necessary to include some details which are relevant to the use of radiation sources in general, although that area is outside the scope of this report. The report is limited to radiation sources made up of radioactive material. The Agency is implementing a comprehensive action plan for assistance to Member States, especially the developing countries, in all aspects of the safe management of spent radiation sources. The Agency is further seeking to establish regional or global solutions to the problems of long-term storage of spent radiation sources, as well as finding routes for the disposal of sources when it is not feasible to set up safe national solutions. The cost of remedial actions after an accident with radiation sources can be very high indeed: millions of dollars. If the Agency can help to prevent even one such single accident, the cost of its whole programme in this field would be more than covered. Refs

Regulatory control of radiation sources. Safety guide

International Nuclear Information System (INIS)

2004-01-01

The basic requirements for the protection of persons against exposure to ionizing radiation and for the safety of radiation sources were established in the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (the Basic Safety Standards), jointly sponsored by the Food and Agriculture Organization of the United Nations (FAO), the International Atomic Energy Agency (IAEA), the International Labour Organization (ILO), the OECD Nuclear Energy Agency (OECD/ NEA), the Pan American Health Organization (PAHO) and the World Health Organization (WHO) (the Sponsoring Organizations). The application of the Basic Safety Standards is based on the presumption that national infrastructures are in place to enable governments to discharge their responsibilities for radiation protection and safety. Requirements relating to the legal and governmental infrastructure for the safety of nuclear facilities and sources of ionizing radiation, radiation protection, the safe management of radioactive waste and the safe transport of radioactive material are established in the Safety Requirements on Legal and Governmental Infrastructure for Nuclear, Radiation, Radioactive Waste and Transport Safety, Safety Standards Series No. GS-R-1. This Safety Guide, which is jointly sponsored by the FAO, the IAEA, the International Labour Office, the PAHO and the WHO, gives detailed guidance on the key elements for the organization and operation of a national regulatory infrastructure for radiation safety, with particular reference to the functions of the national regulatory body that are necessary to ensure the implementation of the Basic Safety Standards. The Safety Guide is based technically on material first published in IAEA-TECDOC-10671, which was jointly sponsored by the FAO, the IAEA, the OECD/NEA, the PAHO and the WHO. The requirements established in GS-R-1 have been taken into account. The Safety Guide is oriented towards national

Control of radioisotopes and radiation sources in Indonesia

International Nuclear Information System (INIS)

Ridwan, M.

2001-01-01

Radioisotopes and radiation sources are extensively used in Indonesia in medicine, industry, mining, agriculture and research. These materials are controlled by the regulatory authority, according to established legal procedures. The Nuclear Energy Control Board of Indonesia (BAPETEN), which was established in 1998 through the Nuclear Energy Act No. 10/1997, is entrusted with the control of any application of nuclear energy, including the application of radioisotopes and radiation sources, through regulation, licensing and inspection. The control is aimed to assure welfare, security and peace, the safety and health of workers and the public, and environmental protection. The number of licences issued to date is around 2400, consisting of 1600 licences for radioisotopes and radiation sources used in hospitals, 347 in radiography, 256 in industry, 53 in mining, and the rest in many other areas such as research and agriculture. A licence can cover one or more radioisotopes or radiation sources, depending on the location of the user institution. These radioisotopes and radiation sources are Co-60, Cs-137, Ir-192, Ra-226, Am-241, Sr-90, Kr-85, Pm-147, linear accelerator and X-ray, and short half-life radioisotopes such as I-125, I-131 and Tc-99m. There are 10 LINACs, 27 X-ray medicines, 61 radioisotope devices for Co-60 and Cs-137, and 10 mHDR Ir-192 for therapeutic purposes currently used in Indonesia and some Ra-226 in storage. Any activity related to the application of nuclear energy is required to be conducted in a manner which observes safety and security. According to the legal requirements, each user has to employ at least one radiation safety officer. To improve the control of the application of radiation sources and radioactive material in the country, BAPETEN introduced some new approaches to the users, including regular dialogues with radiation safety officers and the management of the users, requalification for radiation protection officers twice in five

WADOSE, Radiation Source in Vitrification Waste Storage Apparatus

International Nuclear Information System (INIS)

Morita, Jun-ichi; Tashiro, Shingo; Kikkawa, Shizuo; Tsuboi, Takashi

2007-01-01

1 - Description of program or function: This is a radiation shielding program which analyzes unknown dose rates using known radiation sources. It can also evaluate radiation sources from measured dose rates. For instance, dose rates measured at several points in the hot cell of WASTEF are introduced into WADOS, and as a result, Ci of radiation sources and their positions are estimated with structural arrangement data of the WASTEF cells. The later functional addition is very useful for actual operation of a hot cell and others. NEA-1142/02: The code was originally written in non standard Fortran dialect and has been fully translated into Fortran 90, Fortran 77 compatible. 2 - Method of solution: Point kernel ray tracing method (the same method as QAD code). 3 - Restrictions on the complexity of the problem: Modeling of source form for input is available for cylinder, plate, point and others which are simplified geometrically

The effect of multimicrophone noise reduction systems on sound source localization by users of binaural hearing aids.

Science.gov (United States)

Van den Bogaert, Tim; Doclo, Simon; Wouters, Jan; Moonen, Marc

2008-07-01

This paper evaluates the influence of three multimicrophone noise reduction algorithms on the ability to localize sound sources. Two recently developed noise reduction techniques for binaural hearing aids were evaluated, namely, the binaural multichannel Wiener filter (MWF) and the binaural multichannel Wiener filter with partial noise estimate (MWF-N), together with a dual-monaural adaptive directional microphone (ADM), which is a widely used noise reduction approach in commercial hearing aids. The influence of the different algorithms on perceived sound source localization and their noise reduction performance was evaluated. It is shown that noise reduction algorithms can have a large influence on localization and that (a) the ADM only preserves localization in the forward direction over azimuths where limited or no noise reduction is obtained; (b) the MWF preserves localization of the target speech component but may distort localization of the noise component. The latter is dependent on signal-to-noise ratio and masking effects; (c) the MWF-N enables correct localization of both the speech and the noise components; (d) the statistical Wiener filter approach introduces a better combination of sound source localization and noise reduction performance than the ADM approach.

Disk shaped radiation sources for education purposes made of chemical fertilizer

International Nuclear Information System (INIS)

Kawano, Takao

2008-01-01

A method for fabricating a disk-shaped radiation source from material containing natural radioisotopes was developed. In this compression and formation method, a certain amount of powdered material is placed in a stainless steel formwork and compressed to form a solid disk. Using this method, educational radiation sources were fabricated using commercially available chemical fertilizers that naturally contain the radionuclide, 40 K, which emits either beta or gamma rays, at each disintegration. The compression and formation method was evaluated by inspecting eleven radiation sources thus fabricated. Then the suitability of the fertilizer radiation source as an education aid was evaluated. The results showed that the method could be used to fabricate radiation sources without the need for learning special skills or techniques. It was also found that the potassium fertilizer radiation source could be used to demonstrate that the inverse-square law can be applied to the distance between the radiation source and detector, and that an exponential relationship can be seen between the shielding effectiveness and the total thickness of the shielding materials. It is concluded that a natural fertilizer radiation source is an appropriate aid for demonstrating the characteristics of radiation. (author)

Establishing control over nuclear materials and radiation sources in Georgia

International Nuclear Information System (INIS)

Basilia, G.

2010-01-01

Regulatory control over radiation sources in Georgia was lost after disintegration of the Soviet Union. A number of radiation accidents and illegal events occurred in Georgia. From 1999 Nuclear and Radiation Safety Service of the Ministry of Environmental Protection and Natural Resources is responsible for regulatory control over radiation sources in Georgia. US NRC Regulatory Assistance Program in Georgia Assist the Service in establishing long term regulatory control over sources. Main focuses of US NRC program are country-wide inventory, create National Registry of sources, safe storage of disused sources, upgrade legislation and regulation, implementation licensing and inspection activities

The sound power emitted by a source of low acoustic impedance

DEFF Research Database (Denmark)

Jacobsen, Finn; Verholt, Lars M.

1998-01-01

Several authors have maintained that a source of low acoustic impedance (which includes standardised reference sources of the aerodynamic type) would radiate less than the free field power in a reverberation room. However, neither computer simulations nor experiments have confirmed this assertion....

Physics of Acoustic Radiation from Jet Engine Inlets

Science.gov (United States)

Tam, Christopher K. W.; Parrish, Sarah A.; Envia, Edmane; Chien, Eugene W.

2012-01-01

Numerical simulations of acoustic radiation from a jet engine inlet are performed using advanced computational aeroacoustics (CAA) algorithms and high-quality numerical boundary treatments. As a model of modern commercial jet engine inlets, the inlet geometry of the NASA Source Diagnostic Test (SDT) is used. Fan noise consists of tones and broadband sound. This investigation considers the radiation of tones associated with upstream propagating duct modes. The primary objective is to identify the dominant physical processes that determine the directivity of the radiated sound. Two such processes have been identified. They are acoustic diffraction and refraction. Diffraction is the natural tendency for an acoustic wave to follow a curved solid surface as it propagates. Refraction is the turning of the direction of propagation of sound waves by mean flow gradients. Parametric studies on the changes in the directivity of radiated sound due to variations in forward flight Mach number and duct mode frequency, azimuthal mode number, and radial mode number are carried out. It is found there is a significant difference in directivity for the radiation of the same duct mode from an engine inlet when operating in static condition and in forward flight. It will be shown that the large change in directivity is the result of the combined effects of diffraction and refraction.

Optical Imaging of Ionizing Radiation from Clinical Sources.

Science.gov (United States)

Shaffer, Travis M; Drain, Charles Michael; Grimm, Jan

2016-11-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

Science.gov (United States)

Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

1996-01-01

An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

Active control of turbulent boundary layer-induced sound transmission through the cavity-backed double panels

Science.gov (United States)

Caiazzo, A.; Alujević, N.; Pluymers, B.; Desmet, W.

2018-05-01

This paper presents a theoretical study of active control of turbulent boundary layer (TBL) induced sound transmission through the cavity-backed double panels. The aerodynamic model used is based on the Corcos wall pressure distribution. The structural-acoustic model encompasses a source panel (skin panel), coupled through an acoustic cavity to the radiating panel (trim panel). The radiating panel is backed by a larger acoustic enclosure (the back cavity). A feedback control unit is located inside the acoustic cavity between the two panels. It consists of a control force actuator and a sensor mounted at the actuator footprint on the radiating panel. The control actuator can react off the source panel. It is driven by an amplified velocity signal measured by the sensor. A fully coupled analytical structural-acoustic model is developed to study the effects of the active control on the sound transmission into the back cavity. The stability and performance of the active control system are firstly studied on a reduced order model. In the reduced order model only two fundamental modes of the fully coupled system are assumed. Secondly, a full order model is considered with a number of modes large enough to yield accurate simulation results up to 1000 Hz. It is shown that convincing reductions of the TBL-induced vibrations of the radiating panel and the sound pressure inside the back cavity can be expected. The reductions are more pronounced for a certain class of systems, which is characterised by the fundamental natural frequency of the skin panel larger than the fundamental natural frequency of the trim panel.

Categorization of radioactive sources. Revision of IAEA-TECDOC-1191, Categorization of radiation sources

International Nuclear Information System (INIS)

2003-07-01

Radioactive sources are used throughout the world for a wide variety of peaceful purposes in industry, medicine, agriculture, research and education; and they are also used in military applications. The International Basic Safety Standards provide an internationally harmonized basis for ensuring the safe and secure use of sources of ionizing radiation. Because of the wide variety of uses and activities of radiation sources, a categorization system is necessary so that the controls that are applied to the sources are commensurate with the radiological risks. In September 1998, following an assessment of the major findings of the first International Conference on the Safety of Radiation Sources and the Security of Radioactive Materials, held in Dijon, France, from 14 to 18 September 1998 (the Dijon Conference), the IAEA's General Conference (in resolution GC(42)/RES/12), inter alia, encouraged all governments 'to take steps to ensure the existence within their territories of effective national systems of control for ensuring the safety of radiation sources and the security of radioactive materials' and requested the Secretariat 'to prepare for the consideration of the Board of Governors a report on: (i) how national systems for ensuring the safety of radiation sources and the security of radioactive materials can be operated at a high level of effectiveness; and, (ii) whether international undertakings concerned with the effective operation of such systems and attracting broad adherence could be formulated'. In February 1999, the Secretariat submitted to the IAEA Board of Governors a report prepared in response to the request made of it by the General Conference. The Board took up the report at its March 1999 session and, inter alia, requested the Secretariat to prepare an action plan that took into account the conclusions and recommendations in the report, and the Board's discussion of the report. In August 1999, the Secretariat circulated a proposed Action Plan for

Propagation of sound

DEFF Research Database (Denmark)

Wahlberg, Magnus; Larsen, Ole Næsbye

2017-01-01

properties can be modified by sound absorption, refraction, and interference from multi paths caused by reflections.The path from the source to the receiver may be bent due to refraction. Besides geometrical attenuation, the ground effect and turbulence are the most important mechanisms to influence...... communication sounds for airborne acoustics and bottom and surface effects for underwater sounds. Refraction becomes very important close to shadow zones. For echolocation signals, geometric attenuation and sound absorption have the largest effects on the signals....

Development of Yb-169 radiation source for new nondestructive inspection

International Nuclear Information System (INIS)

Yamabayashi, Hisamichi

1994-01-01

As the nondestructive inspection method for large structures, there has been radiography, and X-ray and γ-ray have been used as the radiation. The transmissivity of radiation through materials changes by the energy of the radiation and the density and thickness of the materials. At present about 880 γ-ray radiography apparatuses are used in Japanese private enterprises, and about 70% of them use 192 Ir γ-ray sources, and about 30% use 60 Co or 137 Cs sources. Recently the defect inspection for the worlded parts of thin wall small tubes and so on have become to be regarded as important, and the 169 Yb source that emits lower energy γ-ray is suitable to the purpose. There are many reports that 169 Yb radiography was applied successfully. As the 169 Yb radiation source, pellets and balls are on the market. 169 Yb is made by the neutron irradiation of 168 Yb in nuclear reactors. The characteristics of 169 Yb, the manufacture of 169 Yb radiation sources and the applicability of 169 Yb radiation sources to nondestructive inspection are reported. Also in Japan, many basic experiments on 169 Yb radiation sources have been carried out, and the irradiation apparatuses are small and light, and the control area can be set small. (K.I.)

Sound spectrum of a pulsating optical discharge

Energy Technology Data Exchange (ETDEWEB)

Grachev, G N; Smirnov, A L; Tishchenko, V N [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Dmitriev, A K; Miroshnichenko, I B [Novosibirsk State Technical University (Russian Federation)

2016-02-28

A spectrum of sound of an optical discharge generated by a repetitively pulsed (RP) laser radiation has been investigated. The parameters of laser radiation are determined at which the spectrum of sound may contains either many lines, or the main line at the pulse repetition rate and several weaker overtones, or a single line. The spectrum of sound produced by trains of RP radiation comprises the line (and overtones) at the repetition rate of train sequences and the line at the repetition rate of pulses in trains. A CO{sub 2} laser with the pulse repetition rate of f ≈ 3 – 180 kHz and the average power of up to 2 W was used in the experiments. (optical discharges)

Radiation sources and process

International Nuclear Information System (INIS)

Honious, H.B.; Janzow, E.F.; Malson, H.A.; Moyer, S.E.

1980-01-01

The invention relates to radiation sources comprising a substrate having an electrically-conductive non-radioactive metal surface, a layer of a metal radioactive isotope of the scandium group, which in addition to scandium, yttrium, lanthanum and actinium, includes all the lanthanide and actinide series of elements, with the actinide series usually being preferred because of the nature of the radioactive isotopes therein, particularly americium-241, curium-244, plutonium-238, californium-252 and promethium-147, and a non-radioactive bonding metal codeposited on the surface by electroplating the isotope and bonding metal from an electrolytic solution, the isotope being present in the layer in minor amount as compared to the bonding metal, and with or without a non-radioactive protective metal coating covering the isotoype and bonding metal on the surface, the coating being sufficiently thin to permit radiation to pass through the coating. The invention also relates to a process for providing radiation sources comprising codepositing a layer of the metal radioactive isotope with a non-radioactive bonding metal from an electrolytic solution in which the isotope is present in minor molar amount as compared to the bonding metal such that the codeposited layer contains a minor molar amount of the isotope compared to the bonding metal by electroplating on an electrically-conductive non-radioactive metal surface of a cathode substrate, and with or without depositing a nonradioactive protective metal coating over the isotope and bonding metal on the surface, the coating being sufficiently thin to permit radiation to pass through the coating

Overview of terahertz radiation sources

International Nuclear Information System (INIS)

Gallerano, G.P.; Biedron, S.G.

2004-01-01

Although terahertz (THz) radiation was first observed about hundred years ago, the corresponding portion of the electromagnetic spectrum has been for long time considered a rather poorly explored region at the boundary between the microwaves and the infrared. This situation has changed during the past ten years with the rapid development of coherent THz sources, such as solid state oscillators, quantum cascade lasers, optically pumped solid state devices and novel free electron devices, which have in turn stimulated a wide variety of applications from material science to telecommunications, from biology to biomedicine. For a comprehensive review of THz technology the reader is addressed to a recent paper by P. Siegel. In this paper we focus on the development and perspectives of THz radiation sources.

Opo lidar sounding of trace atmospheric gases in the 3 - 4 μm spectral range

Science.gov (United States)

Romanovskii, Oleg A.; Sadovnikov, Sergey A.; Kharchenko, Olga V.; Yakovlev, Semen V.

2018-04-01

The applicability of a KTA crystal-based laser system with optical parametric oscillators (OPO) generation to lidar sounding of the atmosphere in the spectral range 3-4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases (TAG) is based on differential absorption lidar (DIAL) method and differential optical absorption spectroscopy (DOAS). The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases. The numerical simulation performed shows that a KTA-based OPO laser is a promising source of radiation for remote DIAL-DOAS sounding of the TAGs under study along surface tropospheric paths. A possibility of using a PD38-03-PR photodiode for the DIAL gas analysis of the atmosphere is shown.

All-fiber femtosecond Cherenkov radiation source

DEFF Research Database (Denmark)

Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe

2012-01-01

-conversion medium, we demonstrate milliwatt-level, stable, and tunable Cherenkov radiation at visible wavelengths 580–630 nm, with pulse duration of sub-160-fs, and the 3 dB spectral bandwidth not exceeding 36 nm. Such an all-fiber Cherenkov radiation source is promising for practical applications in biophotonics...

Devices for obtaining information about radiation sources

International Nuclear Information System (INIS)

Tosswill, C.H.

1981-01-01

The invention provides a sensitive, fast high-resolution device for obtaining information about the distribution of gamma and X-radiation sources and provides a radiation detector useful in such a device. It comprises a slit collimator with a multiplicity of slits each with slit-defining walls of material and thickness to absorb beam components impinging on them. The slits extend further in one direction than the other. The detector for separately detecting beam components passing through the slits also provides data output signals. It comprises a plurality of radiation transducing portions which are not photoconductor elements each at the end of a slit. A positioner operates to change the transverse position of the slits and radiation transducing portions relative to the source, wherein each radiation transducing element is positioned within its respective slit between the slit defining walls. Full details and preferred embodiments are given. (U.K.)

Natural radiation source fabricated from commercially available instant coffee

International Nuclear Information System (INIS)

Kawano, Takao; Ando, Yoshiaki; Izumi, Yuuichi

2015-01-01

Commercially available instant coffee, Nescafe Excella, contained the radionuclide 40 K. From the instant coffee, sixteen coffee-block radiation sources were successfully fabricated with sufficiently low production dependences. The coffee-block radiation sources were examined their suitability for a radiation protection course. Although a part of radiation counts(cpm) obtained with 1 minute measurement were largely deviated, those determined by 5 minute measurements and five times of 1 minute measurement were less deviated, enabling better comprehension of the three cardinal principles of radiation protection. (author)

Protection in handling ionizing radiation sources in national economy

International Nuclear Information System (INIS)

1986-01-01

The collection of study texts is divided into 13 chapters giving an explanation of the structure of the atom, the properties of ionizing radiation and its interactions, quantities and units used, basic dosimetric methods, biological radiation effects, the sources of population exposure, the principles of radiation protection, technological applications of ionizing radiation, the monitoring of personnel and environment, the method of recording and filing, the method of protection from external radiation and internal contamination, health care, and requirements for protection in handling nonsealed sources. (M.D.)

Regulatory control and safety of radiation and radioactive sources in Bangladesh

International Nuclear Information System (INIS)

Mollah, A.S.

2001-01-01

The application of ionizing radiation and radioactive sources in different fields such as, medicine, industry, agriculture, research and teaching is constantly increasing in Bangladesh. Any system enacted to control exposure to ionizing radiation has as primary objective the protection of health of people against the deleterious effects of radiation. Establishing the appropriate level of radiological protection and safety of radiation sources used in practice or intervention attains this objective. The regulatory program governing the safe use of radioactive and radiation sources in Bangladesh is based on the legislation enacted as Nuclear Safety and Radiation Control (NSRC) Act-93 and NSRC Rules-97 and its implementation by the competent authority. The radiation control infrastructures and procedure are described as well as their functioning for the implementation of relevant activities such as licensing, regular inspection, personal dose monitoring, emergency preparedness, etc. The issue of security of radiation source is dealt in close relation with the preparation and use of the inventory of all radiation sources in the country

THE ROLE OF RADIATION ACCIDENTS AND INDUSTRIAL APPLICATIONS OF IONIZING RADIATION SOURCES IN THE PROBLEM OF RADIATION DAMAGE

OpenAIRE

Кіхтенко, Ігор Миколайович

2016-01-01

Subject of research – the relevance of radiation damage at modern development of industry and medicine. In the world of radiation sources used in different fields of practice and their application in the future will increase, which greatly increases the likelihood of injury in a significant contingent of people.Research topic – the definition of the role of nuclear energy and the industrial use of ionizing radiation sources in the problem of radiation damage. The purpose of research – identif...

Devices for obtaining information about radiation sources

International Nuclear Information System (INIS)

Tosswill, C.H.

1981-01-01

The invention provides a sensitive, fast, high-resolution device for obtaining information about the distribution of gamma and X-radiation sources and provides a radiation detector useful in such a device. It comprises a slit collimator with a multiplicity of slits each with slit-defining walls of material and thickness to absorb beam components impinging on them. The slits extend further in one transverse direction than the other. The detector for separately detecting beam components passing through the slits also provides data output signals. It comprises a plurality of radiation transducing portions, each at the end of a slit. A positioner changes the transverse position of the slits and radiation transducer (a photoconductor) relative to the source. Applications are in nuclear medicine and industry. Full details and preferred embodiments are given. (U.K.)

The feasibility of 10 keV X-ray as radiation source in total dose response radiation test

International Nuclear Information System (INIS)

Li Ruoyu; Li Bin; Luo Hongwei; Shi Qian

2005-01-01

The standard radiation source utilized in traditional total dose response radiation test is 60 Co, which is environment-threatening. X-rays, as a new radiation source, has the advantages such as safety, precise control of dose rate, strong intensity, possibility of wafer-level test or even on-line test, which greatly reduce cost for package, test and transportation. This paper discussed the feasibility of X-rays replacing 60 Co as the radiation source, based on the radiation mechanism and the effects of radiation on gate oxide. (authors)

There are radiation sources out there!

International Nuclear Information System (INIS)

Bahran, M.Y.

2001-01-01

During the past few years we have been working in the area of the safety of radiation sources and radioactive materials. In this paper we summarize our findings and describe the recovery of an abandoned source. We call for further international co-operation in this area. In particular, we suggest an international system for the tagging and tracking of radioactive sources. (author)

Dosimetric analysis of radiation sources for use dermatological lesions

International Nuclear Information System (INIS)

Tada, Ariane

2010-01-01

Skin lesions undergoing therapy with radiation sources may have different patterns of malignancy. Malignant lesions or cancer most commonly found in radiotherapy services are carcinomas. Radiation therapy in skin lesions is performed with low penetration beams and orthovoltage X-rays, electron beams and radioactive sources ( 192 Ir, 198 Au, e 90 Sr) arranged on a surface mold or in metal applicator. This study aims to analyze the therapeutic radiation dose profile produced by radiation sources used in skin lesions radiotherapy procedures . Experimental measurements for the analysis of dosimetric radiation sources were compared with calculations obtained from a computer system based on the Monte Carlo Method. Computational results had a good agreement with the experimental measurements. Experimental measurements and computational results by the MCNP4C code were both physically consistent as expected. These experimental measurements compared with calculations using the MCNP-4C code have been used to validate the calculations obtained by MCNP code and to provide a reliable medical application for each clinical case. (author)

Categorization of radiation sources

International Nuclear Information System (INIS)

2000-12-01

The objective of this report is to develop a categorization scheme for radiation sources that could be relevant to decisions both in a retrospective application to bring sources under control and in a prospective sense to guide the application of the regulatory infrastructure. The Action Plan envisages that the preparation of guidance on national strategies and programmes for the detection and location of orphan sources and their subsequent management should commence after the categorization of sources has been carried out. In the prospective application of the system of notification, registration, and licensing, the categorization is relevant to prioritize a regulatory authority's resources and training activities; to guide the degree of detail necessary for a safety assessment; and to serve as a measure of the intensity of effort which a regulatory authority should apply to the safety and security of a particular type of source

The regulatory control of ionizing radiation sources in Lithuania

International Nuclear Information System (INIS)

Mastauskas, A.; Ziliukas, J.; Morkunas, G.

1998-01-01

The Radiation Protection Centre of the Ministry of Health is the regulatory authority responsible for radiation protection of the public and of workers using sources of ionizing radiation in Lithuania. One of its responsibilities is the control of radioactive sources, which includes keeping the registry, investigating persons arrested while illegally carrying or in possession of radioactive material, decision making and control of users of radioactive sources. The computer based registry contains a directory of more than 24,000 sources and some 800 users in research, medicine and industry. Most of these sources are found in smoke detectors and X ray equipment. The potentially most dangerous sources for therapy and industry (sealed and unsealed) are also listed in this registry. Problems connected with the regulatory control of radioactive sources in Lithuania are presented and their solution is discussed. (author)

Ionizing radiation sources management in the Commonwealth of Independent States - CIS

International Nuclear Information System (INIS)

Iskra, A.; Bufetova, M.

2006-01-01

Ionizing radiation sources cover a broad band of power: from powerful NPP reactors and research reactors to portable radioisotope ionizing radiation sources applied in medicine, agriculture, industry and in the energy supply systems of remote facilities. At present, scales and use field of radionuclide sources in the CIS have the tendency to increase. In this connection, the issues of ionizing radiation sources management safety at all stages of their life cycle, from production to treatment, have been of a great importance. The materials on ionizing radiation sources inventory and treatment in the CIS (Russia, Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan and Ukraine) are presented in the report. It is shown that in some republics, there is difficulty in ionizing radiation sources accounting and control system; the national regulatory and legal framework bases regulating activity on radioactive sources use, localization and treatment require update. Many problems are connected with the sources beyond state accounting. The problem of ionizing radiation sources use safety is complicated by the growing activity of various terrorist groups. The opportunity to use ionizing radiation sources with terrorism goals requires the application of defined systems of security and physical protection at all stages of their management. For this purpose a collective, with all CIS countries, organization of radioactive sources accounting and control as well as countermeasures on their illegal transportation and use are necessary. In this connection, the information collection regarding situation with providing of ionizing radiation sources safety, conditions of equipment and storage facilities, radioactive materials accounting and control system in the CIS countries is vitally needed

Spherical loudspeaker array for local active control of sound.

Science.gov (United States)

Rafaely, Boaz

2009-05-01

Active control of sound has been employed to reduce noise levels around listeners' head using destructive interference from noise-canceling sound sources. Recently, spherical loudspeaker arrays have been studied as multiple-channel sound sources, capable of generating sound fields with high complexity. In this paper, the potential use of a spherical loudspeaker array for local active control of sound is investigated. A theoretical analysis of the primary and secondary sound fields around a spherical sound source reveals that the natural quiet zones for the spherical source have a shell-shape. Using numerical optimization, quiet zones with other shapes are designed, showing potential for quiet zones with extents that are significantly larger than the well-known limit of a tenth of a wavelength for monopole sources. The paper presents several simulation examples showing quiet zones in various configurations.

Sound localization and occupational noise

Directory of Open Access Journals (Sweden)

Pedro de Lemos Menezes

2014-02-01

Full Text Available OBJECTIVE: The aim of this study was to determine the effects of occupational noise on sound localization in different spatial planes and frequencies among normal hearing firefighters. METHOD: A total of 29 adults with pure-tone hearing thresholds below 25 dB took part in the study. The participants were divided into a group of 19 firefighters exposed to occupational noise and a control group of 10 adults who were not exposed to such noise. All subjects were assigned a sound localization task involving 117 stimuli from 13 sound sources that were spatially distributed in horizontal, vertical, midsagittal and transverse planes. The three stimuli, which were square waves with fundamental frequencies of 500, 2,000 and 4,000 Hz, were presented at a sound level of 70 dB and were randomly repeated three times from each sound source. The angle between the speaker's axis in the same plane was 45°, and the distance to the subject was 1 m. RESULT: The results demonstrate that the sound localization ability of the firefighters was significantly lower (p<0.01 than that of the control group. CONCLUSION: Exposure to occupational noise, even when not resulting in hearing loss, may lead to a diminished ability to locate a sound source.

Challenges in Regulating Radiation Sources and Associated Waste Management

International Nuclear Information System (INIS)

Shehzad, A.

2016-01-01

Radiation sources are widely used in the fields of medical, industry, agriculture, research, etc. Owing to the inherent risk of exposure to ionizing radiations while using the radiation sources and management of associated waste, safety measures are of utmost importance including robust regulatory control. Pakistan Nuclear Regulatory Authority (PNRA) is responsible for supervising all matters pertaining to nuclear safety and radiation protection in the country. Since its inception, PNRA has made rigorous efforts to regulate the radiation facilities for which regulatory framework was further strengthened by taking into account international norms/practices and implemented afterwards. However, due to vibrant use of these facilities, there are numerous challenges being faced while implementing the regulatory framework. These challenges pertains to shielding design of some facilities, control over service provider for QC/repair maintenance of radiation equipment, assessment of patient doses, and establishment of national diagnostic reference levels for radiological procedures. Further, the regulatory framework also delineate requirements to minimize the generation of associated radioactive waste as low as practicable. The requirements also necessitates that certain sealed radioactive sources (SRS) are returned to the supplier upon completion of their useful life, while other radioactive sources are required to be transported for storage at designated radioactive waste storage facilities in the country, which requires commitment from the licensee. This paper will briefly describe the challenges in regulating the radiation sources and issues related to the waste management associated with these facilities. (author)

On the choice of working conditions for isotope radiation sources in irradiation plants

International Nuclear Information System (INIS)

Syrkus, N.P.; Breger, A.Kh.; Putilov, A.V.

1975-01-01

The problems of selecting an optimal regime for isotopic sources of radiation in powerful radiational installations depending on the costs, parameters of the radiational process (epsilon) and the radioactive isotope halflife are considered. When the radiation sources are simultaneusly replaced, then the optimal time of replacement of sources increases in the radiational installation with the radiation process parameter epsilon<0. Although the cost of a radiational product is lower during continuous replacement of radiation sources, the cost of products in the regime of simultaneous replacement of sources can be decreased, particularly, in the case of a secondary use of the radiactive sources

The regulatory infrastructure for radiation protection, the safety of radiation sources and security of radioactive materials in Ethiopia

International Nuclear Information System (INIS)

Gebeyehu Wolde, G.

2003-01-01

The application of Nuclear Techniques in Ethiopia started in the early sixties in the medical field and through time has gradually expanded to other areas. Following this growth the practice of Radiation Protection in Ethiopia dates back over 15 years. Radiation Protection Legislation 79/1993 was promulgated in December 1993, which has established an Autonomous Regulatory Authority to control and supervise the introduction and conduct of any practice involving ionizing radiation. Since 1998 the National Radiation Protection Authority has made a remarkable progress in terms of building a National Radiation Protection Infrastructure and is in a full swing transformation process towards a dynamic credible and competent regulatory Authority. The regulatory activities are designed in line with the main regulatory instruments, Notification, Authorization, Inspection and Enforcement. NRPA has a national inventory system and fully implemented the Regulatory Authority Information System (RAIS), which provides a systemic integration and will be instrumental to enhance the effectiveness of the regulatory system. A substantial progress has been made in the development and provision of support and technical services in the areas of Metrology and Calibration Services, Instrument Maintenance Service, Individual Monitoring of Personnel, Environmental and Food Monitoring and Interim Storage Facility for spent sources. Development of a national system for emergency preparedness and response is the current top agenda of NRPA. Towards ensuring an effective radiation protection and regulatory programme, NRPA is also making a proactive involvement in, expanding its outreach, information dissemination, awareness promotion and development of key human resources. In the last four years Ethiopia has been actively co-operating with IAEA in the framework of the Regional Model Projects RAF/9/024, RAF/9/028 and RAF/9/029. The inputs received through the project framework coupled with the

Impurity radiation from a beam-plasma neutron source

International Nuclear Information System (INIS)

Molvik, A.W.

1995-01-01

Impurity radiation, in a worst case evaluation for a beam-plasma neutron source (BPNS), does not limit performance. Impurities originate from four sources: (a) sputtering from walls by charge exchange or alpha particle bombardment, (b) sputtering from limiters, (c) plasma desorption of gas from walls and (d) injection with neutral beams. Sources (c) and (d) are negligible; adsorbed gas on the walls of the confinement chamber and the neutral beam sources is removed by the steady state discharge. Source (b) is negligible for impinging ion energies below the sputtering threshold (T i ≤ 0.025 keV on tungsten) and for power densities to the limiter within the capabilities of water cooling (30-40 MW/m 2 ); both conditions can be satisfied in the BPNS. Source (a) radiates 0.025 MW/m 2 to the neutron irradiation samples, compared with 5 to 10 MW/m 2 of neutrons; and radiates a total of 0.08 MW from the plasma column, compared with 60 MW of injected power. The particle bombardment that yields source (a) deposits an average of 2.7 MW/m 2 on the samples, within the capabilities of helium gas cooling (10 MW/m 2 ). An additional worst case for source (d) is evaluated for present day 2 to 5 s pulsed neutral beams with 0.1% impurity density and is benchmarked against 2XIIB. The total radiation would increase a factor of 1.5 to ≤ 0.12 MW, supporting the conclusion that impurities will not have a significant impact on a BPN. (author). 61 refs, 7 figs, 2 tabs

Challenges in Regulating Radiation Sources and Radioactive Waste in Nigeria

International Nuclear Information System (INIS)

Ngwakwe, C.

2016-01-01

Identifying challenges that hamper the efficiency and efficacy of Regulatory Infrastructure (People and Processes) as regards ensuring safety & security of radiation sources and radioactive waste is a major step towards planning for improvement. In a world constantly motivated by technological advancements, there has been considerable increase in the use of new technologies incorporating radioactive sources in both medical and industrial applications due to its perceived benefits, hence changing the dynamics of regulation. This paper brings to the fore, contemporary challenges experienced by regulators in the course of regulating radiation sources and radioactive waste in Nigeria. These challenges encountered in the business of regulating radiation sources and radioactive waste in Nigeria amongst others include; knowledge gap in the use of novel technologies for industrial applications (e.g. radiotracers in oil & gas and wastewater management), inadequate collaboration with operators to ensure transparency in their operations, inadequate cooperation from other government agencies using ionizing radiation sources, lack of synergy between relevant government agencies, difficulty in establishing standard radioactive waste management facility for orphan & disused sources, and inadequate control of NORMS encountered in industrial activities (e.g. well logging, mining). Nigerian Nuclear Regulatory Authority (NNRA), the body saddled with the responsibility of regulating the use of ionizing radiation sources in Nigeria is empowered by the Nuclear Safety and Radiation Protection Act to ensure the protection of life, property, and the environment from the harmful effects of ionizing radiation, hence are not immune to the aforementioned challenges. (author)

Measurement of acoustic characteristics of Japanese Buddhist temples in relation to sound source location and direction.

Science.gov (United States)

Soeta, Yoshiharu; Shimokura, Ryota; Kim, Yong Hee; Ohsawa, Tomohiro; Ito, Ken

2013-05-01

Although temples are important buildings in the Buddhist community, the acoustic quality has not been examined in detail. Buddhist monks change the location and direction according to the ceremony, and associated acoustical changes have not yet been examined scientifically. To discuss the desired acoustics of temples, it is necessary to know the acoustic characteristics appropriate for each phase of a ceremony. In this study, acoustic measurements were taken at various source locations and directions in Japanese temples. A directional loudspeaker was used as the source to provide vocal acoustic fields, and impulse responses were measured and analyzed. The speech transmission index was higher and the interaural cross-correlation coefficient was lower for the sound source directed toward the side wall than that directed toward the altar. This suggests that the change in direction improves speech intelligibility, and the asymmetric property of direct sound and complex reflections from the altar and side wall increases the apparent source width. The large and coupled-like structure of the altar of a Buddhist temple may have reinforced the reverberation components and the table in the altar, which is called the "syumidan," may have decreased binaural coherence.

Sound Radiation from a Supersonic Jet Passing Through a Partially Open Exhaust Duct

Science.gov (United States)

Kandula, Max

2011-01-01

The radiation of sound from a perfectly expanded Mach 2.5 cold supersonic jet of 25.4 mm exit diameter flowing through a partially open rigid-walled duct with an upstream i-deflector has been studied experimentally. In the experiments, the nozzle is mounted vertically, with the nozzle exit plane at a height of 73 jet diameters above ground level. Relative to the nozzle exit plane (NEP), the location of the duct inlet is varied at 10, 5, and -1 jet diameters. Far-field sound pressure levels were obtained at 54 jet diameters above ground with the aid of acoustic sensors equally spaced around a circular arc of radius equal to 80 jet diameters from the jet axis. Data on the jet acoustic field for the partially open duct were obtained and compared with those with a free jet and with a closed duct. The results suggest that for the partially open duct the overall sound pressure level (OASPL) decreases as the distance between the NEP and the duct inlet plane decreases, while the opposite trend is observed for the closed duct. It is also concluded that the observed peak frequency in the partially open duct increases above the free jet value as the angle from the duct axis is increased, and as the duct inlet plane becomes closer to the NEP.

Predicting outdoor sound

CERN Document Server

Attenborough, Keith; Horoshenkov, Kirill

2014-01-01

1. Introduction  2. The Propagation of Sound Near Ground Surfaces in a Homogeneous Medium  3. Predicting the Acoustical Properties of Outdoor Ground Surfaces  4. Measurements of the Acoustical Properties of Ground Surfaces and Comparisons with Models  5. Predicting Effects of Source Characteristics on Outdoor Sound  6. Predictions, Approximations and Empirical Results for Ground Effect Excluding Meteorological Effects  7. Influence of Source Motion on Ground Effect and Diffraction  8. Predicting Effects of Mixed Impedance Ground  9. Predicting the Performance of Outdoor Noise Barriers  10. Predicting Effects of Vegetation, Trees and Turbulence  11. Analytical Approximations including Ground Effect, Refraction and Turbulence  12. Prediction Schemes  13. Predicting Sound in an Urban Environment.

Safety of radiation sources and other radioactive materials in Jordan

International Nuclear Information System (INIS)

Majali, M.M.

2001-01-01

Since joining the IAEA Model Project for upgrading radiation protection infrastructure in countries of West Asia, Jordan has amended its radiation safety legislation. The Regulatory Authority is improving its inventory system for radiation sources and other radioactive materials and also its notification, registration, licensing, inspection and enforcement systems. It has established national provisions for the management of orphan sources after they have been found. The system for the control of the radiation sources and other radioactive materials entering the country has been improved by the Regulatory Authority. (author)

Evaluation of integrity of radiation sources of nuclear gauges

International Nuclear Information System (INIS)

Torohate, Wiclif Francisco

2016-01-01

Nuclear equipment meters are mainly used in the industry in quality control and process control. The principle of operation consists in a shielded radioactive source together with a radiation detector such that the radiation interacts with the material to be analyzed before reaching the detector, providing real time data. Can be as their fixed and mobile mobility, the unique properties of ionizing radiation are used in three basic modes, transmission, backscatter or dispersion or induced (reactive). With the advancement and technological modernization in the world, the demand for nuclear gauges becomes increasingly larger. Currently in Brazil there are about 465 process control plants and 21 portable systems and Mozambique about 45 facilities using nuclear gauges. This font registration is done through a process called source inventory that allows also to know the category of the source, the danger or risk to human health that the source offers. The handling of this equipment requires personnel, certified, skilled and well trained in radiation protection area in accordance with the requirements of the various CNEN Rules. Due to the presence of radioactive source and because these devices are used by workers risk because there external radiation. In this context, we made the smear test in two fixed meters from the IRD industry laboratory, which determines the integrity of the source package, mandatory item in periodic integrity testing of the radiation source of this type of device. A set of procedures is made for its implementation as an evaluation of the radiological risk by radiological survey. It was intended to contribute to the learning handling and safe use of these meters. (author)

Radiometric analyzer with plural radiation sources and detectors

International Nuclear Information System (INIS)

Arima, S.; Oda, M.; Miyashita, K.; Takada, M.

1977-01-01

A radiometric analyzer for measuring characteristics of a material by radiation comprises a plurality of systems in which each consists of a radiation source and a radiation detector which are the same in number as the number of elements of the molecule of the material and a linear calibration circuit having inverse response characteristics (calibration curve) of the respective systems of detectors, whereby the measurement is carried out by four fundamental rules by operation of the mutual outputs of said detector system obtained through said linear calibration circuit. One typical embodiment is a radiometric analyzer for hydrocarbons which measures the density of heavy oil, the sulfur content and the calorific value by three detector systems which include a γ-ray source (E/sub γ/ greater than 50 keV), a soft x-ray source (Ex approximately 20 keV), and a neutron ray source. 2 claims, 6 figures

A holistic approach to hydrocarbon source allocation in the subtidal sediments of Prince William Sound, Alaska, embayments

International Nuclear Information System (INIS)

Page, D.S.; Bence, A.E.; Burns, W.A.; Boehm, P.D.; Brown, J.S.; Douglas, G.S.

2002-01-01

The complex organic geochemistry record in the subtidal sediments of Prince William Sound, Alaska is a result of much industrial and human activity in the region. Recent oil spills and a regional background of natural petroleum hydrocarbons originating from active hydrocarbon systems in the northern Gulf of Alaska also contribute to the geochemical record. Pyrogenic and petrogenic polycyclic aromatic hydrocarbons (PAH) are introduced regularly to the subtidal sediments at sites of past and present human activities including villages, fish hatcheries, fish camps and recreational campsites as well as abandoned settlements, canneries, sawmills and mines. Hydrocarbon contributions are fingerprinted and quantified using a holistic approach where contributions from multiple sources is determined. The approach involves a good understanding of the history of the area to identify potential sources. It also involves extensive collection of representative samples and an accurate quantitative analysis of the source and sediment samples for PAH analytes and chemical biomarker compounds. Total organic carbon (TOC) does not work in restricted embayments because of a constrained least-square algorithm to determine hydrocarbon sources. It has been shown that sources contributing to the natural petrogenic background are present in Prince William Sound. In particular, pyrogenic hydrocarbons such as combustion products of diesel is significant where there was much human activity. In addition, petroleum produced from the Monterey Formation in California is present in Prince William Sound because in the past, oil and asphalt shipped from California was widely used for fuel. Low level residues of weathered Alaskan North Slope crude oil from the Exxon Valdez spill are also still present. 30 refs., 4 tabs., 2 figs

Radiation effects concerns at a spallation source

International Nuclear Information System (INIS)

Sommer, W.F.

1990-01-01

Materials used at spallation neutron sources are exposed to energetic particle and photon radiation. Mechanical and physical properties of these materials are altered; radiation damage on the atomic scale leads to radiation effects on the macroscopic scale. Most notable among mechanical-property radiation effects in metals and metal alloys are changes in tensile strength and ductility, changes in rupture strength, dimensional stability and volumetric swelling, and dimensional changes due to stress-induced creep. Physical properties such as electrical resistivity also are altered. The fission-reactor community has accumulated a good deal of data on material radiation effects. However, when the incident particle energy exceeds 50 MeV or so, a new form of radiation damage ensues; spallation reactions lead to more energetic atom recoils and the subsequent temporal and spatial distribution of point defects is much different from that due to a fission-reactor environment. In addition, spallation reactions cause atomic transmutations with these new atoms representing an impurity in the metal. The higher-energy case is of interest at spallation sources; limited detailed data exist for material performance in this environment. 35 refs., 13 figs., 1 tab

Sources and effects of ionizing radiation. UNSCEAR 2000 report to the General Assembly, with scientific annexes. Volume I: Sources

International Nuclear Information System (INIS)

2000-01-01

Over the past few years the United Nations Scientific Committee on the effects of Atomic Radiation has undertaken a broad review of the sources and effects of ionizing radiation. In the present report, the Committee, drawing on the main conclusions of its scientific assessment summarizes the developments in radiation science in the years leading up to the next millennium. It covers the following: the effects of radiation exposure; levels of radiation exposure; radiological consequences of the Chernobyl accident; sources of radiation exposure including natural exposures, man-made environmental exposures, medical and occupational exposures; radiation associated cancer. This volume includes five Annexes covering: dose assessment methodologies; exposure from natural sources; exposures to the public from man-made sources of radiation and occupational radiation exposures

The actuality and discussion for the data management of radiation sources

International Nuclear Information System (INIS)

Yang Yaoyun; Huang Chaoyun; Wang Xiaofeng; Chen Dongliang; Fu Jie

2008-01-01

Large amounts of data and information in radiation safety license permits, supervision and inspection have been accumulated in China. Data management of radiation sources is an important aspect of radiation sources security. This paper introduces the main elements, tache and actuality of data management, the strengths and weaknesses of RAIS system in use. This paper analyzes and discusses the approach of establishing radiation sources monitoring information system network. (authors)

Occupational exposure to natural sources of radiation

International Nuclear Information System (INIS)

Ortiz, T.; Sciocchetti, G.; Rannou, A.

1993-01-01

The most important natural sources of radiation are analyzed. The situation in France, Italy, and Spain concerning protection against natural radiation is described, including the identification of sources, and defined practices, organizations charged of national surveys and the responsibility of regulatory bodies and the role of operating management. The activities of the international organizations (ICRP, CEC and IAEA) are presented and discussed, and existing actions toward harmonization in the CEC, IAEA and other international programs is also discussed. (R.P.) 23 refs., 2 tabs

New sources of high-power coherent radiation

International Nuclear Information System (INIS)

Sprehngl, F.

1985-01-01

New sources of high-power coherent radiation in the wavelength range from millimeter to ultraviolet are reviewed. Physical mechanisms underlying concepts of free electrons laser, cyclotron resonance laser and other new radiation sources are described. Free electron lasers and cyclotron resonance lasers are shown to suggest excellent possibilities for solving problems of spectroscopy, plasma heating radar and accelerator technology. Results of experiments with free electron laser in the Compton mode using linear accelerators microtrons and storage rings are given. Trends in further investigations are shown

On the influence of microphone array geometry on HRTF-based Sound Source Localization

DEFF Research Database (Denmark)

Farmani, Mojtaba; Pedersen, Michael Syskind; Tan, Zheng-Hua

2015-01-01

The direction dependence of Head Related Transfer Functions (HRTFs) forms the basis for HRTF-based Sound Source Localization (SSL) algorithms. In this paper, we show how spectral similarities of the HRTFs of different directions in the horizontal plane influence performance of HRTF-based SSL...... algorithms; the more similar the HRTFs of different angles to the HRTF of the target angle, the worse the performance. However, we also show how the microphone array geometry can assist in differentiating between the HRTFs of the different angles, thereby improving performance of HRTF-based SSL algorithms....... Furthermore, to demonstrate the analysis results, we show the impact of HRTFs similarities and microphone array geometry on an exemplary HRTF-based SSL algorithm, called MLSSL. This algorithm is well-suited for this purpose as it allows to estimate the Direction-of-Arrival (DoA) of the target sound using any...

Improvements on the directional characteristics of a calibration sound source using the Boundary Element Method

DEFF Research Database (Denmark)

Cutanda Henriquez, Vicente; Barrera Figueroa, Salvador; Juhl, Peter Møller

2008-01-01

The project Euromet-792 aims to investigate and improve methods for secondary free-field calibration of microphones. In this framework, the comparison method is being studied at DFM in relation to the more usual substitution method of microphone calibration. The design of the sound source is of p...

Radiated sound and turbulent motions in a blunt trailing edge flow field

International Nuclear Information System (INIS)

Shannon, Daniel W.; Morris, Scott C.; Mueller, Thomas J.

2006-01-01

The dipole sound produced by edge scattering of pressure fluctuations at a trailing edge is most often an undesirable effect in turbomachinery and control surface flows. The ability to model the flow mechanisms associated with the production of trailing edge acoustics is important for the quiet design of such devices. The objective of the present research was to experimentally measure flow field and acoustic variables in order to develop an understanding of the mechanisms that generate trailing edge noise. The results of these experiments have provided insight into the causal relationships between the turbulent flow field, unsteady surface pressure, and radiated far field acoustics. Experimental methods used in this paper include particle image velocimetry (PIV), unsteady surface pressures, and far field acoustic pressures. The model investigated had an asymmetric 45 o beveled trailing edge. Reynolds numbers based on chord ranged from 1.2 x 10 6 to 1.9 x 10 6 . It was found that the small-scale turbulent motions in the vicinity of the trailing edge were modulated by a large scale von Karman wake instability. The broadband sound produced by these motions was also found to be dependant on the 'phase' of the wake instability

System for actively reducing sound

NARCIS (Netherlands)

Berkhoff, Arthur P.

2005-01-01

A system for actively reducing sound from a primary noise source, such as traffic noise, comprising: a loudspeaker connector for connecting to at least one loudspeaker for generating anti-sound for reducing said noisy sound; a microphone connector for connecting to at least a first microphone placed

Applications and opportunities for radiation sources

International Nuclear Information System (INIS)

Round, K.J.

1984-01-01

An important spin-off benefit from the nuclear industry has been the ability to produce a wide variety of ionizing radiation sources for industrial, medical and scientific applications. These sources include radionuclides produced by irradiation of target material in reactors and cyclotrons or recovered from spent fuels, and accelerators. The uses of radiation in both medicine and industry can be expected to evolve. Traditional uses such as cancer therapy will mature and in some cases be displaced by new technology. Major new applications, including food processing and waste treatment, are expected to maintain the demand for isotopes such as cobalt 60 and to stimulate the development of economical and reliable accelerator systems. (L.L.) (Tab., 2 figs.)

The IAEA Regional Training Course on Regulatory Control of Radiation Sources

International Nuclear Information System (INIS)

2000-01-01

Materials of the IAEA Regional Training Course contains 8 presented lectures. Authors deals with regulatory control of radiation sources. The next materials of the IAEA were presented: Organization and implementation of a national regulatory infrastructure governing protection against ionizing radiation and the safety of radiation sources. (IAEA-TECDOC-1067); Safety assessment plants for authorization and inspection of radiation sources (IAEA-TECDOC-1113); Regulatory authority information system RAIS, Version 2.0, Instruction manual

Radiation sources working group summary

International Nuclear Information System (INIS)

Fazio, M.V.

1998-01-01

The Radiation Sources Working Group addressed advanced concepts for the generation of RF energy to power advanced accelerators. The focus of the working group included advanced sources and technologies above 17 GHz. The topics discussed included RF sources above 17 GHz, pulse compression techniques to achieve extreme peak power levels, components technology, technology limitations and physical limits, and other advanced concepts. RF sources included gyroklystrons, magnicons, free-electron masers, two beam accelerators, and gyroharmonic and traveling wave devices. Technology components discussed included advanced cathodes and electron guns, high temperature superconductors for producing magnetic fields, RF breakdown physics and mitigation, and phenomena that impact source design such as fatigue in resonant structures due to RF heating. New approaches for RF source diagnostics located internal to the source were discussed for detecting plasma and beam phenomena existing in high energy density electrodynamic systems in order to help elucidate the reasons for performance limitations

The energy transport by the propagation of sound waves in wave guides with a moving medium

NARCIS (Netherlands)

le Grand, P.

1977-01-01

The problem of the propagation of sound waves radiated by a source in a fluid moving with subsonic velocity between two parallel walls or inside a cylindrical tube is considered in [2], The most interesting thing of this problem is that waves may occur with constant amplitude coming from infinity.

Analysis and Optimal Condition of the Rear-Sound-Aided Control Source in Active Noise Control

Directory of Open Access Journals (Sweden)

Karel Kreuter

2011-01-01

Full Text Available An active noise control scenario of simple ducts is considered. The previously suggested technique of using an single loudspeaker and its rear sound to cancel the upstream sound is further examined and compared to the bidirectional solution in order to give theoretical proof of its advantage. Firstly, a model with a new approach for taking damping effects into account is derived based on the electrical transmission line theory. By comparison with the old model, the new approach is validated, and occurring differences are discussed. Moreover, a numerical application with the consideration of damping is implemented for confirmation. The influence of the rear sound strength on the feedback-path system is investigated, and the optimal condition is determined. Finally, it is proven that the proposed source has an advantage of an extended phase lag and a time delay in the feedback-path system by both frequency-response analysis and numerical calculation of the time response.

Dosimetric analysis of radiation sources to use in dermatological lesions

International Nuclear Information System (INIS)

Tada, Ariane

2010-01-01

Skin lesions undergoing therapy with radiation sources may have different patterns of malignancy. Malignant lesions or cancer most commonly found in radiotherapy services are carcinomas. Radiation therapy in skin lesions is performed with low penetration beams and orthovoltage X-rays, electron beams and radioactive sources ( 192 Ir, 198 Au, e 90 Sr) arranged on a surface mold or in metal applicator. This study aims to analyze the therapeutic radiation dose profile produced by radiation sources used in skin lesions radiotherapy procedures. Experimental measurements for the analysis of dosimetric radiation sources were compared with calculations obtained from a computer system based on the Monte Carlo Method. Computational results had a good agreement with the experimental measurements. Experimental measurements and computational results by the MCNP4C code have been used to validate the calculations obtained by MCNP code and to provide a reliable medical application for each clinical case. (author)

Determining radiated sound power of building structures by means of laser Doppler vibrometry

Science.gov (United States)

Roozen, N. B.; Labelle, L.; Rychtáriková, M.; Glorieux, C.

2015-06-01

This paper introduces a methodology that makes use of laser Doppler vibrometry to assess the acoustic insulation performance of a building element. The sound power radiated by the surface of the element is numerically determined from the vibrational pattern, offering an alternative for classical microphone measurements. Compared to the latter the proposed analysis is not sensitive to room acoustical effects. This allows the proposed methodology to be used at low frequencies, where the standardized microphone based approach suffers from a high uncertainty due to a low acoustic modal density. Standardized measurements as well as laser Doppler vibrometry measurements and computations have been performed on two test panels, a light-weight wall and a gypsum block wall and are compared and discussed in this paper. The proposed methodology offers an adequate solution for the assessment of the acoustic insulation of building elements at low frequencies. This is crucial in the framework of recent proposals of acoustic standards for measurement approaches and single number sound insulation performance ratings to take into account frequencies down to 50 Hz.

Safety of radiation sources in Slovenia

International Nuclear Information System (INIS)

Belicic-Kolsek, A.; Sutej, T.

2001-01-01

The Republic of Slovenia, a central European country which has been independent since 1991, has about 2 million inhabitants and an area of 20,256 km 2 . The Constitutional Law on Enforcement of the Basic Constitutional Charter on the Autonomy and Independence of the Republic of Slovenia, adopted on 23 June 1991 (Off. Gaz. of the R of Slovenia No. 1/91), provided that all the laws adopted by the Socialist Federal Republic (SFR) of Yugoslavia should remain in force in the Republic of Slovenia pending the adoption of appropriate legislation by the Slovene Parliament. Under the Slovene Constitution, all international treaties ratified by Slovenia constitute an integral part of Slovenia's legislation and can be applied directly. In Slovenia, all regular types of ionizing radiation source are being used for peaceful purposes and are covered by a system for their safe use and control. All radiation sources and radioactive materials are registered and under regulatory control. Inspections are carried out periodically by the Health Inspectorate of the Republic of Slovenia (HIRS) and, in the case of nuclear installations, the Slovene Nuclear Safety Administration (SNSA). Technical checks on radiation sources are carried out periodically by technical support organizations: the Jozef Stefan Institute and the Institute for Occupational Safety (IOS). (author)

Underwater Sound Propagation from Marine Pile Driving.

Science.gov (United States)

Reyff, James A

2016-01-01

Pile driving occurs in a variety of nearshore environments that typically have very shallow-water depths. The propagation of pile-driving sound in water is complex, where sound is directly radiated from the pile as well as through the ground substrate. Piles driven in the ground near water bodies can produce considerable underwater sound energy. This paper presents examples of sound propagation through shallow-water environments. Some of these examples illustrate the substantial variation in sound amplitude over time that can be critical to understand when computing an acoustic-based safety zone for aquatic species.

Assessment of risk from radiation sources

International Nuclear Information System (INIS)

Subbaratnam, T.; Madhvanath, U.; Somasundaram, S.

1976-01-01

Assessment of risk from exposure to ionizing radiations from man-made radiation sources and nuclear installations has to be viewed from three aspects, namely, dose-effect relationship (genetic and somatic) for humans, calculation of doses or dose-commitments to population groups, assessment of risk to radiation workers and the population at large from the current levels of exposure from nuclear industry and comparison of risk estimates with other industries in a modern society. These aspects are discussed in brief. On the basis of available data, it is shown that estimated incidence of genetic diseases and cancers due to exposure of population to radiation from nuclear industry is negligible in comparison with their natural incidence, and radiation risks to the workers in nuclear industry are much lower than the risks in other occupations. (M.G.B.)

Opo lidar sounding of trace atmospheric gases in the 3 – 4 μm spectral range

Directory of Open Access Journals (Sweden)

Romanovskii Oleg A.

2018-01-01

Full Text Available The applicability of a KTA crystal-based laser system with optical parametric oscillators (OPO generation to lidar sounding of the atmosphere in the spectral range 3–4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases (TAG is based on differential absorption lidar (DIAL method and differential optical absorption spectroscopy (DOAS. The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases. The numerical simulation performed shows that a KTA-based OPO laser is a promising source of radiation for remote DIAL-DOAS sounding of the TAGs under study along surface tropospheric paths. A possibility of using a PD38-03-PR photodiode for the DIAL gas analysis of the atmosphere is shown.

Regulatory control for safe usage of ionizing radiation sources in Bangladesh

International Nuclear Information System (INIS)

Mollah, A.S.

2008-01-01

Full text: In Bangladesh, there is a widespread and continuos growth in the use of the ionizing radiation sources both radioactive materials and radiation generating equipment in the field of industry, medicine, agriculture, research, teaching etc. In industry, they are employed in production as well as quality control such as non-destructive testing (radiography), nucleonic gauging, radiotracer techniques and in radiation processing. Medical applications of ionizing radiation include X-ray radiography, X-ray fluoroscopy, CT scan, mammography, nuclear medicine, beam therapy and brachytherapy. Besides radioisotopes are also used for research applications, viz., scattering experiments, tracer studies, etc. In agriculture, the uptake of nutrients by soil, and parts of plants are studied using suitable radionuclides. In all the above applications radioisotopes in two forms namely sealed sources and open sources in different chemical forms are employed with source strengths varying from micro curies to mega curies. The benefits to man from the use of ionizing radiation and sources of radiation are accompanied by risks which may result from exposure of man to ionizing radiation. In order to have an effective control on the use of radiation sources and to ensure radiological safety of the user as well as the public, Government of Bangladesh has promulgated Nuclear Safety and Radiation Control (NSRC) rules 1997 under the NSRC Act 1993. The Bangladesh Atomic Energy commission (BAEC) is the competent authority for formulating rules and regulations for ensuring radiological safety. BAEC is legally responsible for developing and strengthening the necessary radiation protection infrastructure in the country through the effective enforcement and implementation of regulatory requirements, criteria, obligations, guiding, codes etc. in order to save man and the related environment from the deleterious effects of ionizing radiation. In Bangladesh, only those persons who have been

Trends in use of non-medical radiation sources in Slovenia

International Nuclear Information System (INIS)

Giacomelli, M.; Cesarek, J.; Osojnik, I.

2007-01-01

Slovenian Nuclear Safety Administration is the regulatory authority competent also for administrative control in the fields of radiation practices and use of radiation sources in industry and research, with exception in medicine and veterinary medicine. Prior to the adoption of the Act on Protection against Ionizing Radiation and Nuclear Safety the responsible authority was the Health Inspectorate of Republic of Slovenia. The article presents an overview of the use of radiation sources in Slovenia, in industry, research and education. Analysis of the data from abovementioned regulators shall examine trends in use in recent years as number of sources and organizations, and according to the type of their intended use. (author)

Detailed observations of the source of terrestrial narrowband electromagnetic radiation

Science.gov (United States)

Kurth, W. S.

1982-01-01

Detailed observations are presented of a region near the terrestrial plasmapause where narrowband electromagnetic radiation (previously called escaping nonthermal continuum radiation) is being generated. These observations show a direct correspondence between the narrowband radio emissions and electron cyclotron harmonic waves near the upper hybrid resonance frequency. In addition, electromagnetic radiation propagating in the Z-mode is observed in the source region which provides an extremely accurate determination of the electron plasma frequency and, hence, density profile of the source region. The data strongly suggest that electrostatic waves and not Cerenkov radiation are the source of the banded radio emissions and define the coupling which must be described by any viable theory.

Future radiation sources and identification of irradiated foods

International Nuclear Information System (INIS)

Brynjolfsson, A.

1989-01-01

Two major questions regarding irradiation that are raised today are: (1) Which sources should be used for irradiating food? and (2) How can irradiated foods be identified? This article considers both questions. After briefly mentioning a few of the historical stepping stones in the development of radiation sources, present and future radiation sources are discussed. Next the changes in foods caused by irradiation are considered. These changes are extremely small-so minor in fact that it is difficult to detect if the food has been irradiated. Still, these are several detection methods available, and this article describes them

Design of UAV-Embedded Microphone Array System for Sound Source Localization in Outdoor Environments

Directory of Open Access Journals (Sweden)

Kotaro Hoshiba

2017-11-01

Full Text Available In search and rescue activities, unmanned aerial vehicles (UAV should exploit sound information to compensate for poor visual information. This paper describes the design and implementation of a UAV-embedded microphone array system for sound source localization in outdoor environments. Four critical development problems included water-resistance of the microphone array, efficiency in assembling, reliability of wireless communication, and sufficiency of visualization tools for operators. To solve these problems, we developed a spherical microphone array system (SMAS consisting of a microphone array, a stable wireless network communication system, and intuitive visualization tools. The performance of SMAS was evaluated with simulated data and a demonstration in the field. Results confirmed that the SMAS provides highly accurate localization, water resistance, prompt assembly, stable wireless communication, and intuitive information for observers and operators.

Design of UAV-Embedded Microphone Array System for Sound Source Localization in Outdoor Environments.

Science.gov (United States)

Hoshiba, Kotaro; Washizaki, Kai; Wakabayashi, Mizuho; Ishiki, Takahiro; Kumon, Makoto; Bando, Yoshiaki; Gabriel, Daniel; Nakadai, Kazuhiro; Okuno, Hiroshi G

2017-11-03

In search and rescue activities, unmanned aerial vehicles (UAV) should exploit sound information to compensate for poor visual information. This paper describes the design and implementation of a UAV-embedded microphone array system for sound source localization in outdoor environments. Four critical development problems included water-resistance of the microphone array, efficiency in assembling, reliability of wireless communication, and sufficiency of visualization tools for operators. To solve these problems, we developed a spherical microphone array system (SMAS) consisting of a microphone array, a stable wireless network communication system, and intuitive visualization tools. The performance of SMAS was evaluated with simulated data and a demonstration in the field. Results confirmed that the SMAS provides highly accurate localization, water resistance, prompt assembly, stable wireless communication, and intuitive information for observers and operators.

A method for recognition of coexisting environmental sound sources based on the Fisher’s linear discriminant classifier

DEFF Research Database (Denmark)

Creixell Mediante, Ester; Haddad, Karim; Song, Wookeun

2015-01-01

A method for sound recognition of coexisting environmental noise sources by applying pattern recognition techniques is developed. The investigated technique could benefit several areas of application, such as noise impact assessment, acoustic pollution mitigation and soundscape characterization...

The Advanced Light Source (ALS) Radiation Safety System

International Nuclear Information System (INIS)

Ritchie, A.L.; Oldfather, D.E.; Lindner, A.F.

1993-08-01

The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory (LBL) is a 1.5 Gev synchrotron light source facility consisting of a 120 kev electron gun, 50 Mev linear accelerator, 1.5 Gev booster synchrotron, 200 meter circumference electron storage ring, and many photon beamline transport systems for research. Figure 1. ALS floor plan. Pairs of neutron and gamma radiation monitors are shown as dots numbered from 1 to 12. The Radiation Safety System for the ALS has been designed and built with a primary goal of providing protection against inadvertent personnel exposure to gamma and neutron radiation and, secondarily, to enhance the electrical safety of select magnet power supplies

Annual individual doses for personnel dealing with ionizing radiation sources

International Nuclear Information System (INIS)

Poplavskij, K.K.

1982-01-01

Data on annual individual doses for personnel of national economy enterprises, research institutes, high schools, medical establishments dealing with ionizing radiation sources are presented. It is shown that radiation dose for the personnel constitutes only shares of standards established by sanitary legislation. Numeral values of individual doses of the personnel are determined by the type, character and scope of using ionizing radiation sources

ELBE Center for High-Power Radiation Sources

Directory of Open Access Journals (Sweden)

Peter Dr. Michel

2016-01-01

Full Text Available In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR.

The utilization of radiation sources in Angola

International Nuclear Information System (INIS)

Lemos, P.C.D.

2001-01-01

The report describes the situation that Angola, which joined the IAEA in September 1999, is facing with the lack of an appropriate infrastructure for the control of radiation sources. It emphasizes the country's needs in technical assistance from the IAEA and other Member States for improving its regulatory infrastructure for radiation safety. (author)

Radiation safety aspects in the use of radiation sources in industrial and heath-care applications

International Nuclear Information System (INIS)

Venkat Raj, V.

2001-01-01

The principle underlying the philosophy of radiation protection and safety is to ensure that there exists an appropriate standard of protection and safety for humans, without unduly limiting the benefits of the practices giving rise to exposure or incurring disproportionate costs in interventions. To realise these objectives, the International Commission on Radiation Protection (ICRP-60) and IAEA's Safety Series (IAEA Safety Series 120, 1996) have enunciated the following criteria for the application and use of radiation: (1) justification of practices; (2) optimisation of protection; (3) dose limitation and (4) safety of sources. Though these criteria are the basic tenets of radiation protection, the radiation hazard potentials of individual applications vary and the methods to achieve the above mentioned objectives principles are different. This paper gives a brief overview of the various applications of radiation and radioactive sources in India, their radiation hazard perspective and the radiation safety measures provided to achieve the basic radiation protection philosophy. (author)

Radiation problems expected for the German spallation neutron source

International Nuclear Information System (INIS)

Goebel, K.

1981-01-01

The German project for the construction of a Spallation Neutron Source with high proton beam power (5.5 MW) will have to cope with a number of radiation problems. The present report describes these problems and proposes solutions for keeping exposures for the staff and release of activity and radiation into the environment as low as reasonably achievable. It is shown that the strict requirements of the German radiation protection regulations can be met. The main problem will be the exposure of maintenance personnel to remanent gamma radiation, as is the case at existing proton accelerators. Closed ventilation and cooling systems will reduce the release of (mainly short-lived) activity to acceptable levels. Shielding requirements for different sections are discussed, and it is demonstrated by calculations and extrapolations from experiments that fence-post doses well below 150 mrem/y can be obtained at distances of the order of 100 metres from the principal source points. The radiation protection system proposed for the Spallation Neutron Source is discussed, in particular the needs for monitor systems and a central radiation protection data base and alarm system. (orig.)

Optimal Prediction of Moving Sound Source Direction in the Owl.

Directory of Open Access Journals (Sweden)

Weston Cox

2015-07-01

Full Text Available Capturing nature's statistical structure in behavioral responses is at the core of the ability to function adaptively in the environment. Bayesian statistical inference describes how sensory and prior information can be combined optimally to guide behavior. An outstanding open question of how neural coding supports Bayesian inference includes how sensory cues are optimally integrated over time. Here we address what neural response properties allow a neural system to perform Bayesian prediction, i.e., predicting where a source will be in the near future given sensory information and prior assumptions. The work here shows that the population vector decoder will perform Bayesian prediction when the receptive fields of the neurons encode the target dynamics with shifting receptive fields. We test the model using the system that underlies sound localization in barn owls. Neurons in the owl's midbrain show shifting receptive fields for moving sources that are consistent with the predictions of the model. We predict that neural populations can be specialized to represent the statistics of dynamic stimuli to allow for a vector read-out of Bayes-optimal predictions.

A Survey of Sound Source Localization Methods in Wireless Acoustic Sensor Networks

Directory of Open Access Journals (Sweden)

Maximo Cobos

2017-01-01

Full Text Available Wireless acoustic sensor networks (WASNs are formed by a distributed group of acoustic-sensing devices featuring audio playing and recording capabilities. Current mobile computing platforms offer great possibilities for the design of audio-related applications involving acoustic-sensing nodes. In this context, acoustic source localization is one of the application domains that have attracted the most attention of the research community along the last decades. In general terms, the localization of acoustic sources can be achieved by studying energy and temporal and/or directional features from the incoming sound at different microphones and using a suitable model that relates those features with the spatial location of the source (or sources of interest. This paper reviews common approaches for source localization in WASNs that are focused on different types of acoustic features, namely, the energy of the incoming signals, their time of arrival (TOA or time difference of arrival (TDOA, the direction of arrival (DOA, and the steered response power (SRP resulting from combining multiple microphone signals. Additionally, we discuss methods not only aimed at localizing acoustic sources but also designed to locate the nodes themselves in the network. Finally, we discuss current challenges and frontiers in this field.

Sound field separation with cross measurement surfaces.

Directory of Open Access Journals (Sweden)

Jin Mao

Full Text Available With conventional near-field acoustical holography, it is impossible to identify sound pressure when the coherent sound sources are located on the same side of the array. This paper proposes a solution, using cross measurement surfaces to separate the sources based on the equivalent source method. Each equivalent source surface is built in the center of the corresponding original source with a spherical surface. According to the different transfer matrices between equivalent sources and points on holographic surfaces, the weighting of each equivalent source from coherent sources can be obtained. Numerical and experimental studies have been performed to test the method. For the sound pressure including noise after separation in the experiment, the calculation accuracy can be improved by reconstructing the pressure with Tikhonov regularization and the L-curve method. On the whole, a single source can be effectively separated from coherent sources using cross measurement.

The German radiation protection infrastructure with emphasis on the safety of radiation sources and radioactive material

International Nuclear Information System (INIS)

Czarwinski, R.; Weimer, G.

2001-01-01

Through federalism, Germany has a complicated but well functioning regulatory infrastructure for the safety and security of radiation sources based on a clear legal system. The main features of this infrastructure include the legal framework, the authorization and control systems and the responsibilities of different regulatory authorities, which this paper will describe. In connection with the legal framework, the provisions to control the import/export of radiation sources are briefly discussed and some information is given about the registries of sources. Protection and response measures related to unusual events concerning radiation sources, including orphan sources, will be cited. Also, the education and training of different target groups and punitive actions are touched upon in the paper. Conclusions will be drawn for future national and international actions. (author)

International basic safety standards for protecting against ionizing radiation and for the safety of radiation sources

International Nuclear Information System (INIS)

1996-01-01

The purpose of the Standards is to establish basic requirements for protection against the risks associated with exposure to ionizing radiation (hereinafter termed radiation) and for the safety of radiation sources that may deliver such exposure. The Standards have been developed from widely accepted radiation protection and safety principles, such as those published in the Annals of the ICRP and the IAEA Safety Series. They are intended to ensure the safety of all types of radiation sources and, in doing so, to complement standards already developed for large and complex radiation sources, such as nuclear reactors and radioactive waste management facilities. For the sources, more specific standards, such as those issued by the IAEA, are typically needed to achieve acceptable levels of safety. As these more specific standards are generally consistent with the Standards, in complying with them, such more complex installations will also generally comply with the Standards. The Standards are limited to specifying basic requirements of radiation protection and safety, with some guidance on how to apply them. General guidance on applying some of the requirements is available in the publications of the Sponsoring Organizations and additional guidance will be developed as needed in the light of experience gained in the application of the Standards. Tabs

International basic safety standards for protecting against ionizing radiation and for the safety of radiation sources

International Nuclear Information System (INIS)

1997-01-01

The purpose of the Standards is to establish basic requirements for protection against the risks associated with exposure to ionizing radiation (hereinafter termed radiation) and for the safety of radiation sources that may deliver such exposure. The Standards have been developed from widely accepted radiation protection and safety principles, such as those published in the Annals of the ICRP and the IAEA Safety Series. They are intended to ensure the safety of all types of radiation sources and, in doing so, to complement standards already developed for large and complex radiation sources, such as nuclear reactors and radioactive waste management facilities. For the sources, more specific standards, such as those issued by the IAEA, are typically needed to achieve acceptable levels of safety. As these more specific standards are generally consistent with the Standards, in complying with them, such more complex installations will also generally comply with the Standards. The Standards are limited to specifying basic requirements of radiation protection and safety, with some guidance on how to apply them. General guidance on applying some of the requirements is available in the publications of the Sponsoring Organizations and additional guidance will be developed as needed in the light of experience gained in the application of the Standards

Underdense radiation sources: Moving towards longer wavelengths

Energy Technology Data Exchange (ETDEWEB)

Back, C.A.; Kilkenny, J.D. [General Atomics, San Diego, California (United States); Seely, J.F.; Weaver, J.L. [Naval Research Laboratory, Washington, DC (United States); Feldman, U. [Artep Inc., Ellicott City, MD (United States); Tommasini, R.; Glendinning, S.G.; Chung, H.K.; Rosen, M.; Lee, R.W.; Scott, H.A. [Lawrence Livermore National Laboratory, California (United States); Tillack, M. [U. C. San Diego, La Jolla, CA (United States)

2006-06-15

Underdense radiation sources have been developed to provide efficient laboratory multi-keV radiation sources for radiography and radiation hardening studies. In these plasmas laser absorption by inverse Bremsstrahlung leads to high x-ray conversion efficiency because of efficient ionization of the low density aerogel or gas targets. Now we performing experiments in the soft x-ray energy regime where the atomic physics models are much more complicated. In recent experiments at the NIKE laser, we have irradiated a Ti-doped SiO{sub 2} aerogel with up to 1650 J of 248 nm wavelength light. The absolute Ti L-shell emission in the 200-800 eV range is measured with a diagnostic that uses a transmission grating coupled to Si photodiodes. We will give an overview of the temporally-resolved absolutely calibrated spectra obtained over a range of conditions. (authors)

Underdense radiation sources: Moving towards longer wavelengths

International Nuclear Information System (INIS)

Back, C.A.; Kilkenny, J.D.; Seely, J.F.; Weaver, J.L.; Feldman, U.; Tommasini, R.; Glendinning, S.G.; Chung, H.K.; Rosen, M.; Lee, R.W.; Scott, H.A.; Tillack, M.

2006-01-01

Underdense radiation sources have been developed to provide efficient laboratory multi-keV radiation sources for radiography and radiation hardening studies. In these plasmas laser absorption by inverse Bremsstrahlung leads to high x-ray conversion efficiency because of efficient ionization of the low density aerogel or gas targets. Now we performing experiments in the soft x-ray energy regime where the atomic physics models are much more complicated. In recent experiments at the NIKE laser, we have irradiated a Ti-doped SiO 2 aerogel with up to 1650 J of 248 nm wavelength light. The absolute Ti L-shell emission in the 200-800 eV range is measured with a diagnostic that uses a transmission grating coupled to Si photodiodes. We will give an overview of the temporally-resolved absolutely calibrated spectra obtained over a range of conditions. (authors)

Sterilization plants equipped with the isotopic gamma radiation sources

International Nuclear Information System (INIS)

Mehta, K.; Chmielewski, A.G.

2007-01-01

Presentation describes different isotopic gamma radiation sources applicable for sterilization of food and medical materials. Certain gamma pallet irradiators, mini gamma irradiators and different scale gamma tote irradiators are presented. It is concluded, that about two hundreds plants with gamma radiation sources operates in different countries. However, industrially developed countries must construct much more plants than operates now

A general description of the Swedish radiation protection regulations of radioactive sources

International Nuclear Information System (INIS)

Staalnacke, C.-G.

2001-01-01

The regulation of ionizing radiation in Sweden is based on both the Radiation Protection Act and Ordinance from 1998. The Swedish Radiation Protection Institute (SSI) acts as the regulatory authority for radiation safety and issues detailed regulations in specific areas. The report summarizes how the SSI controls radiation sources, including orphan sources for which a process for analyzing their occurrence has started in Sweden. A number of proposed procedures for the control and follow-up of sealed radioactive sources is provided. (author)

Licensing authority's control of radiation sources and nuclear materials in Brazil

International Nuclear Information System (INIS)

Binns, D.A.C.

2002-01-01

Full text: The Brazilian Nuclear Energy Commission is the national licensing authority and among its responsibilities is the control of nuclear materials and radiation sources. This control is carried out in three different ways: 1) Control of the import and export of nuclear materials and radiation sources. To be able to import or export any nuclear material or radiation source, the user has to have an explicit permission of the licensing authority. This is controlled by electronic means in which the user has to fill a special form found on the licensing authority's home page, where he has to fill in his name, license number, license number of his radiation protection officer and data of the material to be imported or exported. These data are checked with a data base that contains all the information of the licensed users and qualified personnel before authorization is emitted. The airport authorities have already installed x-ray machines to check all baggages entering or leaving the country. 2) Transport and transfer permit for radiation sources. In order to transport and/or transfer radiations sources and nuclear materials within the country, the user(s) have to submit an application to the licensing authority. The user(s) fill out an application form where he fills in his company's name, licensing I.D., radiation protection officer's name and I.D and identification of the sources involved. These information are checked with the licensing operations data before the operations is permitted. 3) Inspections and radiation monitoring systems. Routine and regulatory inspections are continuously carried out where the user's radiation sources and nuclear materials inventory are checked. Also the physical security and protection of these materials are verified. The installation of monitoring systems is an item that is being discussed with the airport authorities so as to increase the possibilities of detecting any illegal transport of these materials. (author)

Abnormal sound detection device

International Nuclear Information System (INIS)

Yamada, Izumi; Matsui, Yuji.

1995-01-01

Only components synchronized with rotation of pumps are sampled from detected acoustic sounds, to judge the presence or absence of abnormality based on the magnitude of the synchronized components. A synchronized component sampling means can remove resonance sounds and other acoustic sounds generated at a synchronously with the rotation based on the knowledge that generated acoustic components in a normal state are a sort of resonance sounds and are not precisely synchronized with the number of rotation. On the other hand, abnormal sounds of a rotating body are often caused by compulsory force accompanying the rotation as a generation source, and the abnormal sounds can be detected by extracting only the rotation-synchronized components. Since components of normal acoustic sounds generated at present are discriminated from the detected sounds, reduction of the abnormal sounds due to a signal processing can be avoided and, as a result, abnormal sound detection sensitivity can be improved. Further, since it is adapted to discriminate the occurrence of the abnormal sound from the actually detected sounds, the other frequency components which are forecast but not generated actually are not removed, so that it is further effective for the improvement of detection sensitivity. (N.H.)

Sound propagation in cities

NARCIS (Netherlands)

Salomons, E.; Polinder, H.; Lohman, W.; Zhou, H.; Borst, H.

2009-01-01

A new engineering model for sound propagation in cities is presented. The model is based on numerical and experimental studies of sound propagation between street canyons. Multiple reflections in the source canyon and the receiver canyon are taken into account in an efficient way, while weak

Sound radiation quantities arising from a resilient circular radiator

NARCIS (Netherlands)

Aarts, R.M.; Janssen, A.J.E.M.

2009-01-01

Power series expansions in ka are derived for the pressure at the edge of a radiator, the reaction force on the radiator, and the total radiated power arising from a harmonically excited, resilient, flat, circular radiator of radius a in an infinite baffle. The velocity profiles on the radiator are

Spike-timing-based computation in sound localization.

Directory of Open Access Journals (Sweden)

Dan F M Goodman

2010-11-01

Full Text Available Spike timing is precise in the auditory system and it has been argued that it conveys information about auditory stimuli, in particular about the location of a sound source. However, beyond simple time differences, the way in which neurons might extract this information is unclear and the potential computational advantages are unknown. The computational difficulty of this task for an animal is to locate the source of an unexpected sound from two monaural signals that are highly dependent on the unknown source signal. In neuron models consisting of spectro-temporal filtering and spiking nonlinearity, we found that the binaural structure induced by spatialized sounds is mapped to synchrony patterns that depend on source location rather than on source signal. Location-specific synchrony patterns would then result in the activation of location-specific assemblies of postsynaptic neurons. We designed a spiking neuron model which exploited this principle to locate a variety of sound sources in a virtual acoustic environment using measured human head-related transfer functions. The model was able to accurately estimate the location of previously unknown sounds in both azimuth and elevation (including front/back discrimination in a known acoustic environment. We found that multiple representations of different acoustic environments could coexist as sets of overlapping neural assemblies which could be associated with spatial locations by Hebbian learning. The model demonstrates the computational relevance of relative spike timing to extract spatial information about sources independently of the source signal.

Evaluation of methods to leak test sealed radiation sources

International Nuclear Information System (INIS)

Arbeau, N.D.; Scott, C.K.

1987-04-01

The methods for the leak testing of sealed radiation sources were reviewed. One hundred and thirty-one equipment vendors were surveyed to identify commercially available leak test instruments. The equipment is summarized in tabular form by radiation type and detector type for easy reference. The radiation characteristics of the licensed sources were reviewed and summarized in a format that can be used to select the most suitable detection method. A test kit is proposed for use by inspectors when verifying a licensee's test procedures. The general elements of leak test procedures are discussed

Source Separation of Heartbeat Sounds for Effective E-Auscultation

Science.gov (United States)

Geethu, R. S.; Krishnakumar, M.; Pramod, K. V.; George, Sudhish N.

2016-03-01

This paper proposes a cost effective solution for improving the effectiveness of e-auscultation. Auscultation is the most difficult skill for a doctor, since it can be acquired only through experience. The heart sound mixtures are captured by placing the four numbers of sensors at appropriate auscultation area in the body. These sound mixtures are separated to its relevant components by a statistical method independent component analysis. The separated heartbeat sounds can be further processed or can be stored for future reference. This idea can be used for making a low cost, easy to use portable instrument which will be beneficial to people living in remote areas and are unable to take the advantage of advanced diagnosis methods.

Recent paleoseismicity record in Prince William Sound, Alaska, USA

Science.gov (United States)

Kuehl, Steven A.; Miller, Eric J.; Marshall, Nicole R.; Dellapenna, Timothy M.

2017-12-01

Sedimentological and geochemical investigation of sediment cores collected in the deep (>400 m) central basin of Prince William Sound, along with geochemical fingerprinting of sediment source areas, are used to identify earthquake-generated sediment gravity flows. Prince William Sound receives sediment from two distinct sources: from offshore (primarily Copper River) through Hinchinbrook Inlet, and from sources within the Sound (primarily Columbia Glacier). These sources are found to have diagnostic elemental ratios indicative of provenance; Copper River Basin sediments were significantly higher in Sr/Pb and Cu/Pb, whereas Prince William Sound sediments were significantly higher in K/Ca and Rb/Sr. Within the past century, sediment gravity flows deposited within the deep central channel of Prince William Sound have robust geochemical (provenance) signatures that can be correlated with known moderate to large earthquakes in the region. Given the thick Holocene sequence in the Sound ( 200 m) and correspondingly high sedimentation rates (>1 cm year-1), this relationship suggests that sediments within the central basin of Prince William Sound may contain an extraordinary high-resolution record of paleoseismicity in the region.

The international standard for protection from ionizing radiation and safety of radiation sources

Energy Technology Data Exchange (ETDEWEB)

Schlesinger, T [Israel Atomic Energy Commission, Yavne (Israel). Soreq Nuclear Research Center

1995-06-01

This document is a review in hebrew of the new 1994 international standard of the IAEA. The new standard title is `Basic safety standards for radiation protection and for the safety of radiation sources`, which were published in the ICRP Pub. 9.

Training of human resources on radiation protection and safe use of radiation sources. Argentine experience

International Nuclear Information System (INIS)

Biaggio, Alfredo L.; Nasazzi, Nora B.; Arias, Cesar

2004-01-01

Argentina has a long experience in Radiation Protection training since 25 years ago. In the present work we analyse those variable and non variable training aspects according to scientific development, increasing radiation source diversity (including new concepts like orphan sources and security), mayor concern about patient in Radiation Protection, previous exposures, etc. We comment what we consider the main steps in the training of Radiation Protection specialists, like university degree, post graduate education distinguishing between formative and informative contents and on the job training. Moreover, we point out the trainees aptitudes and attitudes to be developed in order to work properly in this interdisciplinary field. (author)

TEMPORAL AND SPATIAL VARIATION IN SOLAR RADIATION AND PHOTO-ENHANCED TOXICITY RISKS OF SPILLED OIL IN PRINCE WILLIAM SOUND, ALASKA

Science.gov (United States)

Solar irradiance (W/m2) and downwelling diffuse attenuation coefficients (Kd; m-1) were determined in several locations in Prince William Sound, Alaska, USA, between April 2003 and December 2005 to assess temporal and spatial variation in solar radiation and the risks of photoenh...

State Register of Sources of Ionizing Radiation and Occupational exposure

CERN Document Server

2002-01-01

One of main tasks of Radiation Protection Centre is to collect, process, systematize, store and provide the data on sources of ionizing radiation and occupational exposures. The number of sources in 2002 is provided and compared with previous year. Distribution of workers according to the type of practice is compared with previous year. Distribution of sealed sources and x-ray machines according their use is presented.

Patch near-field acoustic holography: The influence of acoustic contributions from outside the source

DEFF Research Database (Denmark)

Fernandez Grande, Efren; Jacobsen, Finn; Zhang, Yong-Bin

2009-01-01

It is a requirement of conventional Near-field Acoustic Holography that the measurement area covers the entire surface of the source. In the case of Patch Near-field Acoustic Holography (patch NAH), the measurement area can be reduced to cover only a specific area of the source which...... is of particular interest (known as the “patch” or “source patch”). The area of the source beyond this patch is not of interest in the analysis. However, its acoustic output may nevertheless contribute to the total sound field in the measurement plane, and influence the reconstruction of the field close...... to the patch. The purpose of this paper is to investigate how the acoustic radiation from outside the patch area influences the reconstruction of the sound field close to the source. The reconstruction is based on simulated measurements of sound pressure and particle velocity. The methods used in this paper...

Sustainably Sourced, Thermally Resistant, Radiation Hard Biopolymer

Science.gov (United States)

Pugel, Diane

2011-01-01

This material represents a breakthrough in the production, manufacturing, and application of thermal protection system (TPS) materials and radiation shielding, as this represents the first effort to develop a non-metallic, non-ceramic, biomaterial-based, sustainable TPS with the capability to also act as radiation shielding. Until now, the standing philosophy for radiation shielding involved carrying the shielding at liftoff or utilizing onboard water sources. This shielding material could be grown onboard and applied as needed prior to different radiation landscapes (commonly seen during missions involving gravitational assists). The material is a bioplastic material. Bioplastics are any combination of a biopolymer and a plasticizer. In this case, the biopolymer is a starch-based material and a commonly accessible plasticizer. Starch molecules are composed of two major polymers: amylase and amylopectin. The biopolymer phenolic compounds are common to the ablative thermal protection system family of materials. With similar constituents come similar chemical ablation processes, with the potential to have comparable, if not better, ablation characteristics. It can also be used as a flame-resistant barrier for commercial applications in buildings, homes, cars, and heater firewall material. The biopolymer is observed to undergo chemical transformations (oxidative and structural degradation) at radiation doses that are 1,000 times the maximum dose of an unmanned mission (10-25 Mrad), indicating that it would be a viable candidate for robust radiation shielding. As a comparison, the total integrated radiation dose for a three-year manned mission to Mars is 0.1 krad, far below the radiation limit at which starch molecules degrade. For electron radiation, the biopolymer starches show minimal deterioration when exposed to energies greater than 180 keV. This flame-resistant, thermal-insulating material is non-hazardous and may be sustainably sourced. It poses no hazardous

Sound radiation from finite surfaces

DEFF Research Database (Denmark)

Brunskog, Jonas

2013-01-01

A method to account for the effect of finite size in acoustic power radiation problem of planar surfaces using spatial windowing is developed. Cremer and Heckl presents a very useful formula for the power radiating from a structure using the spatially Fourier transformed velocity, which combined...... with spatially windowing of a plane waves can be used to take into account the finite size. In the present paper, this is developed by means of a radiation impedance for finite surfaces, that is used instead of the radiation impedance for infinite surfaces. In this way, the spatial windowing is included...

Statistics of natural binaural sounds.

Directory of Open Access Journals (Sweden)

Wiktor Młynarski

Full Text Available Binaural sound localization is usually considered a discrimination task, where interaural phase (IPD and level (ILD disparities at narrowly tuned frequency channels are utilized to identify a position of a sound source. In natural conditions however, binaural circuits are exposed to a stimulation by sound waves originating from multiple, often moving and overlapping sources. Therefore statistics of binaural cues depend on acoustic properties and the spatial configuration of the environment. Distribution of cues encountered naturally and their dependence on physical properties of an auditory scene have not been studied before. In the present work we analyzed statistics of naturally encountered binaural sounds. We performed binaural recordings of three auditory scenes with varying spatial configuration and analyzed empirical cue distributions from each scene. We have found that certain properties such as the spread of IPD distributions as well as an overall shape of ILD distributions do not vary strongly between different auditory scenes. Moreover, we found that ILD distributions vary much weaker across frequency channels and IPDs often attain much higher values, than can be predicted from head filtering properties. In order to understand the complexity of the binaural hearing task in the natural environment, sound waveforms were analyzed by performing Independent Component Analysis (ICA. Properties of learned basis functions indicate that in natural conditions soundwaves in each ear are predominantly generated by independent sources. This implies that the real-world sound localization must rely on mechanisms more complex than a mere cue extraction.

Statistics of natural binaural sounds.

Science.gov (United States)

Młynarski, Wiktor; Jost, Jürgen

2014-01-01

Binaural sound localization is usually considered a discrimination task, where interaural phase (IPD) and level (ILD) disparities at narrowly tuned frequency channels are utilized to identify a position of a sound source. In natural conditions however, binaural circuits are exposed to a stimulation by sound waves originating from multiple, often moving and overlapping sources. Therefore statistics of binaural cues depend on acoustic properties and the spatial configuration of the environment. Distribution of cues encountered naturally and their dependence on physical properties of an auditory scene have not been studied before. In the present work we analyzed statistics of naturally encountered binaural sounds. We performed binaural recordings of three auditory scenes with varying spatial configuration and analyzed empirical cue distributions from each scene. We have found that certain properties such as the spread of IPD distributions as well as an overall shape of ILD distributions do not vary strongly between different auditory scenes. Moreover, we found that ILD distributions vary much weaker across frequency channels and IPDs often attain much higher values, than can be predicted from head filtering properties. In order to understand the complexity of the binaural hearing task in the natural environment, sound waveforms were analyzed by performing Independent Component Analysis (ICA). Properties of learned basis functions indicate that in natural conditions soundwaves in each ear are predominantly generated by independent sources. This implies that the real-world sound localization must rely on mechanisms more complex than a mere cue extraction.

Ocular exposure to ultraviolet and visible radiation from light sources

International Nuclear Information System (INIS)

Hietanen, M.

1992-01-01

Exposure of the eyes to UV radiation and blue light of artificial light sources and the sun was evaluated. A spectroradiometer was used to determine the spectral irradiance at 1 nm intervals from 250 to 800 nm. Various groups of workers are at risk of ocular over-exposure to optical radiation, outdoor workers maintenance personnel of bright light source as and wear eye-protectors with effective filtering of UV radiation and blue light. (author)

Control of sources of ionizing radiation in Lithuania

International Nuclear Information System (INIS)

Mastauskas, Albinas; Ziliukas, Julius; Morkunas, Gendrutis

1997-01-01

Aspects connected with regulatory control of radioactive sources in Lithuania, such as keeping of the computer-based registry, investigation of arrested illegal radioactive material, decision making, control of users of radioactive sources are discussed. Most of the sources of ionizing radiation are smoke detectors and x-ray equipment. Potentially most dangerous sources (both sealed and unsealed) of therapy and industry are also presented

Application of large radiation sources in chemical processing industry

International Nuclear Information System (INIS)

Krishnamurthy, K.

1977-01-01

Large radiation sources and their application in chemical processing industry are described. A reference has also been made to the present developments in this field in India. Radioactive sources, notably 60 Co, are employed in production of wood-plastic and concrete-polymer composites, vulcanised rubbers, polymers, sulfochlorinated paraffin hydrocarbons and in a number of other applications which require deep penetration and high reliability of source. Machine sources of electrons are used in production of heat shrinkable plastics, insulation materials for cables, curing of paints etc. Radiation sources have also been used for sewage hygienisation. As for the scene in India, 60 Co sources, gamma chambers and batch irradiators are manufactured. A list of the on-going R and D projects and organisations engaged in research in this field is given. (M.G.B.)

Aircrew radiation exposure: sources-risks-measurement

International Nuclear Information System (INIS)

Duftschmid, K.E.

1994-05-01

A short review is given on the actual aircrew exposure and its sources. The resulting risks for harmful effects to the health and discuss methods for in-flight measurements of exposure is evaluated. An idea for a fairly simple and economic approach to a practical, airborne active dosimeter for the assessment of individual crew exposure is presented. The exposure of civil aircrew to cosmic radiation, should not be considered a tremendous risk to the health, there is no reason for panic. However, being significantly higher than the average exposure to radiation workers, it can certainly not be neglected. As recommended by ICRP, aircrew exposure has to be considered occupational radiation exposure and aircrews are certainly entitled to the same degree of protection, as other ground-based radiation workers have obtained by law, since long time. (author)

Protection during work with ionizing radiation sources; Ochrana pri praci se zdroji ionizujiciho zareni

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

The publication has been set up as a textbook for training courses dealing with health protection during work with ionizing radiation, designed for supervisory staff and persons directly responsible for activities which involve the handling of ionizing radiation sources. The book consists of a preface and the following chapters: (1) Fundamentals of ionizing radiation physics; (2) Quantities and units used in ionizing radiation protection; (3) Principles of ionizing radiation dosimetry; (4) Biological effects of ionizing radiation; (5) An overview of sources of public irradiation; (6) Principles and methods of health protection against ionizing radiation; (7) Examples of technical applications of sources of ionizing radiation; (8) Personnel and working environment monitoring; (9) Documentation maintained at sites with ionizing radiation sources; (10) Methods of personnel protection against external irradiation and internal radionuclide contamination; (11) Radiation incidents and accidents; (12) Health care of personnel exposed to the ionizing radiation risk; (12) Additional radiation protection requirements in handling radioactive substances other than sealed sources; (13) Measurement and metrology. (P.A.).

Sound Power Minimization of Circular Plates Through Damping Layer Placement

Science.gov (United States)

Wodtke, H.-W.; Lamancusa, J. S.

1998-09-01

Damping layers, widely used for noise and vibration control of thin-walled structures, can be designed to provide an optimal trade-off between performance and weight which is of particular importance in the automotive and aircraft industry. The goal of the presented work is the minimization of sound power radiated from plates under broadband excitation by redistribution of unconstrained damping layers. The total radiated sound power is assumed to be represented by the sound power radiated at the structural resonances. Resonance tracking is performed by means of single-degree-of-freedom (SDOF)-approximations based on near-resonance responses and their frequency derivatives. Axisymmetric vibrations of circular plates under several boundary and forcing conditions are considered. Frequency dependent Young's modulus and loss factor of the damping material are taken into account. Vibration analysis is based on the finite element method (FEM) while acoustic radiation is treated by means of Rayleigh's integral formula. It is shown that, starting from a uniform damping layer distribution, substantial reduction in radiated sound power can be achieved through redistribution of the damping layers. Depending on the given situation, these reductions are not only due to amplitude reductions but also to changes in vibration shapes and frequencies.

Hybrid Active/Passive Control of Sound Radiation from Panels with Constrained Layer Damping and Model Predictive Feedback Control

Science.gov (United States)

Cabell, Randolph H.; Gibbs, Gary P.

2000-01-01

There has been considerable interest over the past several years in applying feedback control methods to problems of structural acoustics. One problem of particular interest is the control of sound radiation from aircraft panels excited on one side by a turbulent boundary layer (TBL). TBL excitation appears as many uncorrelated sources acting on the panel, which makes it difficult to find a single reference signal that is coherent with the excitation. Feedback methods have no need for a reference signal, and are thus suited to this problem. Some important considerations for the structural acoustics problem include the fact that the required controller bandwidth can easily extend to several hundred Hertz, so a digital controller would have to operate at a few kilohertz. In addition, aircraft panel structures have a reasonably high modal density over this frequency range. A model based controller must therefore handle the modally dense system, or have some way to reduce the bandwidth of the problem. Further complicating the problem is the fact that the stiffness and dynamic properties of an aircraft panel can vary considerably during flight due to altitude changes resulting in significant resonant frequency shifts. These considerations make the tradeoff between robustness to changes in the system being controlled and controller performance especially important. Recent papers concerning the design and implementation of robust controllers for structural acoustic problems highlight the need to consider both performance and robustness when designing the controller. While robust control methods such as H1 can be used to balance performance and robustness, their implementation is not easy and requires assumptions about the types of uncertainties in the plant being controlled. Achieving a useful controller design may require many tradeoff studies of different types of parametric uncertainties in the system. Another approach to achieving robustness to plant changes is to

Personnel selection and training for radiation protection and safe use of radiation sources

International Nuclear Information System (INIS)

Gomaa, M.A.

2000-01-01

For proper implementation of the radiation protection programs in the work place, several persons with different qualifications and training are involved. Among these persons are regulatory personnel managers, operators, workers, health professional, health physics technicians, health physicists, qualified experts, and emergency personnel. The current status of education and training of these persons is discussed in order to build competence in radiation protection and the safe use of radiation sources

The Advanced Light Source (ALS) Radiation Safety System

International Nuclear Information System (INIS)

Ritchie, A.; Oldfather, D.; Lindner, A.

1993-05-01

The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory (LBL) is a 1.5 GeV synchrotron light source facility consisting of a 120 keV electron gun, 50 MeV linear accelerator, 1.5 Gev booster synchrotron, 200 meter circumference electron storage ring, and many photon beamline transport systems for research. The Radiation Safety System for the ALS has been designed and built with a primary goal of providing protection against inadvertent personnel exposure to gamma and neutron radiation and, secondarily, to enhance the electrical safety of select magnet power supplies

Radiation in the living environment: sources, exposure and effects

International Nuclear Information System (INIS)

Gupta, Rashi

2013-01-01

We are living in a milieu of radiations and continuously exposed to radiations from natural sources from conception to death. We are exposed to radiation from Sun and outer space, radioactive materials present in the earth, house we live in, buildings and workplace, food we eat and air we breath. Each flake of snow, grain of soil, drop of rain, a flower, and even each man in the street is a source of this radiation. Even our own bodies contain naturally occurring radioactive elements. The general belief is that the radiations are harmful and everybody is scared of the same. The cancer is the most important concern on account of exposure to Ionizing Radiation which is initiated by the damage to DNA. The level of exposure depends on the environmental and working conditions and may vary from low to moderate to high and depending on the same the exposed humans can be classified as general public, non nuclear workers (NNW) and nuclear workers (NW). Though, the LNT theory which is considered to be the radiation paradigm considers all radiation at all levels to be harmful and the -severity of the deleterious effect increases with the increase in dose, however, the available literature, data and reports (epidemiological and experimental) speaks otherwise particularly at low levels. The purpose of this paper is to address the question, whether the radiation is harmful at all levels or it is simply media hype and the truth is different, and to promote harmony with nature and to improve our quality of life with the knowledge that cancer mortality rates decrease following exposure to LLIR. Various sources of radiation exposure and the subsequent consequences will be discussed. (author)

Dosimetry services for internal and external radiation sources

International Nuclear Information System (INIS)

1988-01-01

The Canadian Atomic Energy Control Board (AECB) sets radiation dose limits for the operation of nuclear facilities and the possession of prescribed substances within Canada. To administer these regulations the AECB must be satisfied that the dosimetry services used by a licensee meet adequate standards. Licensees are required to use the Occupational Dosimetry Service operated by the Bureau of Radiation and Medical Devices, Department of National Health and Welfare (BRMD) to determine doses from external sources of radiation, except where a detailed rationale is given for using another service. No national dosimetry service exists for internal sources of radiation. Licensees who operate or use a dosimetry service other than the BRMD must provide the AECB with evidence of the competence of the staff and adequacy of the equipment, techniques and procedures; provide the AECB with evidence that a quality assurance program has been implemented; and send individual dose or exposure data to the National Dose Registry. (L.L.)

Strengthening the security of radiation sources in Ghana

International Nuclear Information System (INIS)

Emi-Reynolds, G.; Banini, G.K.; Flecther, J.J.; Ennison, I.; Schandorf, C.

1998-01-01

Legislative instrument LI 1559 of 1993 established the Radiation Protection Board (RPB) as the National Competent Authority (NCA) on radiation matters in Ghana. The Board advises Government through the Ghana Atomic Energy Commission on matters relating to radiation safety, security of sources, sales, import and export, contamination in food and environment, among others. It has wide ranging regulatory power and works in association with country authorities. The regulations in place for controlling the movement and use of radioactive materials in Ghana are discussed. Accountability for radioactive materials especially for those which were brought in before the establishment of the RPB have been the focus of our discussion. The need to for intensify educational programs for the public on matters relating to effect of radiation on man and environment is recommended. Strengthening of regulatory control of sources and intensifying efforts against smuggling, unauthorised use and systems for notification on radioactive transport accidents are noted. (author)

Design of UAV-Embedded Microphone Array System for Sound Source Localization in Outdoor Environments †

Science.gov (United States)

Hoshiba, Kotaro; Washizaki, Kai; Wakabayashi, Mizuho; Ishiki, Takahiro; Bando, Yoshiaki; Gabriel, Daniel; Nakadai, Kazuhiro; Okuno, Hiroshi G.

2017-01-01

In search and rescue activities, unmanned aerial vehicles (UAV) should exploit sound information to compensate for poor visual information. This paper describes the design and implementation of a UAV-embedded microphone array system for sound source localization in outdoor environments. Four critical development problems included water-resistance of the microphone array, efficiency in assembling, reliability of wireless communication, and sufficiency of visualization tools for operators. To solve these problems, we developed a spherical microphone array system (SMAS) consisting of a microphone array, a stable wireless network communication system, and intuitive visualization tools. The performance of SMAS was evaluated with simulated data and a demonstration in the field. Results confirmed that the SMAS provides highly accurate localization, water resistance, prompt assembly, stable wireless communication, and intuitive information for observers and operators. PMID:29099790

Radiation sources in the EU. A review of steps in the European Union

International Nuclear Information System (INIS)

Ciani, V.

1999-01-01

This article reviews the role and activities of the European Union concerning safety of radiation sources. A brief presentation is given of the results from a recent study of the management of radiation sources in EU Member Sates. A Number of legal texts which apply to radiation sources are cited as well. In 1998, the EC co-sponsored together with the IAEA, the International Criminal Police Organization and the World Customs Organization, a Conference on the safety of radiation Sources and the Security of Radioactive Materials in France. Commission supports follow-up actions to that Conference and welcomes the IAEA initiative to develop an action plan that would address the international dimensions of the safety of radiation sources

Numerical Solution of the Kzk Equation for Pulsed Finite Amplitude Sound Beams in Thermoviscous Fluids

Science.gov (United States)

Lee, Yang-Sub

A time-domain numerical algorithm for solving the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear parabolic wave equation is developed for pulsed, axisymmetric, finite amplitude sound beams in thermoviscous fluids. The KZK equation accounts for the combined effects of diffraction, absorption, and nonlinearity at the same order of approximation. The accuracy of the algorithm is established via comparison with analytical solutions for several limiting cases, and with numerical results obtained from a widely used algorithm for solving the KZK equation in the frequency domain. The time domain algorithm is used to investigate waveform distortion and shock formation in directive sound beams radiated by pulsed circular piston sources. New results include predictions for the entire process of self-demodulation, and for the effect of frequency modulation on pulse envelope distortion. Numerical results are compared with measurements, and focused sources are investigated briefly.

Halifax Sound Range Trials (DE0301, EK500)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Radiated sound measurements of vessels are important for monitoring the noise characteristics of fishing and research vessels. A vessel's radiated noise can have...

Overview in Argentina on spent/disused radiation sources

International Nuclear Information System (INIS)

Lavalle, M.B.

2001-01-01

Argentine nuclear activities have begun since about 1950. Since those days the peaceful applications of nuclear energy have been developed and together with then radioactive wastes have taken more and more relevance day by day. To deal with this special subject the Radioactive Waste Management Programme (RWMP) has been established. Spent/disused radiation sources are a very important task to consider in the management of radioactive waste. A great number of sources have been received along these years by the RWMP. Different sources categories handled together with their figures and radionuclide activities will be presented. Also described will be the steps that have to be followed by the users/owners of spent/disused radiation sources to transfer them to the RWMP. Once the sources are in the RWMP custody, they can be stored or they can be conditioned in order to be stored in an interim storage or disposed of. It is shown how the different sources are managed, taking into account the radionuclide's half life, its activity and the available facilities. Besides a record-keeping system for tracking all spent/disused radiation sources has been developed. It consists on a computerized database that contains essential information about the sources as well as the whole radioactive wastes managed by the RWMP. The main objective of the waste management registry-database system is to collect, identify, process and follow the related information about the radioactive wastes among al the management steps. It is also able to calculate the actualized activity inventory for the storage and final disposal facilities. In order to implement this system, it was necessary to write the related technical documentation. These documents established the radioactive waste acceptance requirements, that together with others integrates the Quality Assurance System applied to the radioactive waste management. Regarding the disused sources little could be done. They are stored in an appropriate

Heat Transfer by Thermo-capillary Convection -Sounding Rocket COMPERE Experiment SOURCE

Science.gov (United States)

Dreyer, Michael; Fuhrmann, Eckart

The sounding rocket COMPERE experiment SOURCE was successfully flown on MASER 11, launched in Kiruna (ESRANGE), May 15th, 2008. SOURCE has been intended to partly ful-fill the scientific objectives of the European Space Agency (ESA) Microgravity Applications Program (MAP) project AO-2004-111 (Convective boiling and condensation). Three parties of principle investigators have been involved to design the experiment set-up: ZARM for thermo-capillary flows, IMFT (Toulouse, France) for boiling studies, EADS Astrium (Bremen, Ger-many) for depressurization. The topic of this paper is to study the effect of wall heat flux on the contact line of the free liquid surface and to obtain a correlation for a convective heat trans-fer coefficient. The experiment has been conducted along a predefined time line. A preheating sequence at ground was the first operation to achieve a well defined temperature evolution within the test cell and its environment inside the rocket. Nearly one minute after launch, the pressurized test cell was filled with the test liquid HFE-7000 until a certain fill level was reached. Then the free surface could be observed for 120 s without distortion. Afterwards, the first depressurization was started to induce subcooled boiling, the second one to start saturated boiling. The data from the flight consists of video images and temperature measurements in the liquid, the solid, and the gaseous phase. Data analysis provides the surface shape versus time and the corresponding apparent contact angle. Computational analysis provides information for the determination of the heat transfer coefficient in a compensated gravity environment where a flow is caused by the temperature difference between the hot wall and the cold liquid. The paper will deliver correlations for the effective contact angle and the heat transfer coefficient as a function of the relevant dimensionsless parameters as well as physical explanations for the observed behavior. The data will be used

Transformation of second sound into surface waves in superfluid helium

International Nuclear Information System (INIS)

Khalatnikov, I.M.; Kolmakov, G.V.; Pokrovsky, V.L.

1995-01-01

The Hamiltonian theory of superfluid liquid with a free boundary is developed. Nonlinear amplitudes of parametric Cherenkov radiation of a surface wave by second sound and the inner decay of second sound waves are found. Threshold amplitudes of second sound waves for these two processes are determined. 4 refs

Regulatory control of radiation sources in the Philippines

Energy Technology Data Exchange (ETDEWEB)

Daroy, Rosita R

1996-12-31

This paper is concerned with the radiation protection and safety infrastructure providing emphasis on the regulation and control of radiation sources in the Philippines. It deals with the experiences of the Philippine Nuclear Research Institute, as a regulatory body, in the regulation and control of radioactive materials in radiotherapy, nuclear medicine, industrial radiography, industrial gauges, industrial irradiators, and well logging. This paper includes an inventory of the sources and types of devices/equipment used by licensed users of radioactive materials in the Philippines as a contribution to the data base being prepared by the IAEA. The problems encountered by the regulatory body in the licensing and enforcement process, as well as the lessons learned from incidents involving radioactive materials are discussed. Plans for improving compliance to the regulations and enhancing the effectiveness of PNRI`s regulatory functions are presented. (author). Paper presented during the IAEA Regional (RCA) Workshop on System of Notification, Registration, Licensing, and Control of Radiation Sources and Installations, Jakarta, Indonesia, 24-28 April 1995. 6 refs., 2 figs., 12 tabs.

Compact high-power terahertz radiation source

Directory of Open Access Journals (Sweden)

G. A. Krafft

2004-06-01

Full Text Available In this paper a new type of THz radiation source, based on recirculating an electron beam through a high gradient superconducting radio frequency cavity, and using this beam to drive a standard electromagnetic undulator on the return leg, is discussed. Because the beam is recirculated and not stored, short bunches may be produced that radiate coherently in the undulator, yielding exceptionally high average THz power for relatively low average beam power. Deceleration from the coherent emission, and the detuning it causes, limits the charge-per-bunch possible in such a device.

Exposures to natural radiation sources. Annex B

International Nuclear Information System (INIS)

1982-01-01

The assessment of the radiation doses from natural sources in humans is presented. Both external sources of extraterrestrial origin (cosmic rays) and of terrestrial origin, and internal sources, comprising the naturally-occurring radionuclides which are taken into the human body, are discussed. This Annex is to a large extent a summary of Annex B of the 1977 report of the Committee. The doses due to the radon isotopes and to their short-lived decay products are briefly reviewed.

On Distributions of Emission Sources and Speed-of-Sound in Proton-Proton (Proton-Antiproton Collisions

Directory of Open Access Journals (Sweden)

Li-Na Gao

2015-01-01

Full Text Available The revised (three-source Landau hydrodynamic model is used in this paper to study the (pseudorapidity distributions of charged particles produced in proton-proton and proton-antiproton collisions at high energies. The central source is assumed to contribute with a Gaussian function which covers the rapidity distribution region as wide as possible. The target and projectile sources are assumed to emit isotropically particles in their respective rest frames. The model calculations obtained with a Monte Carlo method are fitted to the experimental data over an energy range from 0.2 to 13 TeV. The values of the squared speed-of-sound parameter in different collisions are then extracted from the width of the rapidity distributions.

Data survey about radiation protection and safety of radiation sources in research laboratories

International Nuclear Information System (INIS)

Paura, Clayton L.; Dantas, Ana Leticia A.; Dantas, Bernardo M.

2005-01-01

In Brazil, different types of research using unsealed sources are developed with a variety of radioisotopes. In such activities, professionals and students involved are potentially exposed to internal contamination by 14 C, 45 Ca, 51 Cr, 3 H, 125 I, 32 P, 33 P, 35 S, 90 Sr and 99m Tc. The general objective of this work is to evaluate radiological risks associated to these practices in order to supply information for planning actions aimed to improve radiation protection conditions in research laboratories. The criteria for risk evaluation and the safety aspects adopted in this work were based on CNEN Regulation 6.02 and in IAEA and NRPB publications. The survey of data was carried out during visits to laboratories in public Universities located in the city of Rio de Janeiro where unsealed radioactive sources are used in biochemistry, biophysics and genetic studies. According to the criteria adopted in this work, some practices developed in the laboratories require evaluation of risk of internal contamination depending on the conditions of source manipulation. It was verified the need for training of users of radioactive materials in this type of laboratory. This can be facilitated by the use of basic guides for the classification of areas, radiation protection, safety and source security in research laboratories. It was also observed the need for optimization of such practices in order to minimize the contact with sources. It is recommended to implement more effective source and access controls as a way to reduce risks of individual radiation exposure and loss of radioactive materials (author)

Standard Syllabus for Postgraduate Educational Courses in Radiation Protection and the Safe use of Radiation Sources

International Nuclear Information System (INIS)

Arias, C.; Biaggio, A.; Nasazzi, N.

2004-01-01

The International Atomic Energy Agency (IAEA) published the Standard Syllabus for Post Graduate Educational Courses in Radiation Protection and the Safety of Radiation Sources in 2002. Along more than two decades, Argentina has obtained valuable experience on building professional knowledge at postgraduate level in Radiation Protection and Nuclear Safety. Such experience made advisable to review the IAEA Standard Syllabus and to modify it accordingly. The whole content of the Standard Syllabus is included in the syllabus developed for the Argentinean Regional Post Graduate Course in Radiation Protection and Safety of Radiation Sources. But a few additional topics were incorporated and changes were introduced in the sequence of subjects. The paper describes those modifications and explains the pedagogic motivations that induce them. (Author) 3 refs

Radiation Sources Working Group Summary Report

International Nuclear Information System (INIS)

Fazio, Michael V.

1999-01-01

The Radiation Sources Working Group addressed advanced concepts for the generation of RF energy to power advanced accelerators. The focus of the working group included advanced sources and technologies above 17 GHz. The topics discussed included RF sources above 17 GHz, pulse compression techniques to achieve extreme peak power levels, component technology, technology limitations and physical limits, and other advanced concepts. RF sources included gyroklystrons, magnicons, free-electron masers, two beam accelerators, and gyroharmonic and traveling wave devices. Technology components discussed included advanced cathodes and electron guns, high temperature superconductors for producing magnetic fields, RF breakdown physics and mitigarion, and phenomena that impact source design such as fatigue in resonant structures due to pulsed RF heating. New approaches for RF source diagnostics located internal to the source were discussed for detecting plasma and beam phenomena existing in high energy density electrodynamic systems in order to help elucidate the reasons for performance limitations

Radiation Sources Working Group Summary Report

International Nuclear Information System (INIS)

Fazio, M.V.

1999-01-01

The Radiation Sources Working Group addressed advanced concepts for the generation of RF energy to power advanced accelerators. The focus of the working group included advanced sources and technologies above 17 GHz. The topics discussed included RF sources above 17 GHz, pulse compression techniques to achieve extreme peak power levels, component technology, technology limitations and physical limits, and other advanced concepts. RF sources included gyroklystrons, magnicons, free-electron masers, two beam accelerators, and gyroharmonic and traveling wave devices. Technology components discussed included advanced cathodes and electron guns, high temperature superconductors for producing magnetic fields, RF breakdown physics and mitigarion, and phenomena that impact source design such as fatigue in resonant structures due to pulsed RF heating. New approaches for RF source diagnostics located internal to the source were discussed for detecting plasma and beam phenomena existing in high energy density electrodynamic systems in order to help elucidate the reasons for performance limitations. copyright 1999 American Institute of Physics

Stability of high-brilliance synchrotron radiation sources

International Nuclear Information System (INIS)

Chattopadhyay, S.

1989-12-01

This paper discusses the following topics: characteristics of synchrotron radiation sources; stability of the orbits; orbit control; nonlinear dynamic stability; and coherent stability and control. 1 ref., 5 figs., 1 tab

Vibrational mode and sound radiation of electrostatic speakers using circular and annular diaphragms

Science.gov (United States)

Huang, Yu-Hsi; Chiang, Hsin-Yuan

2016-06-01

This study modeled two diaphragms comprising a pair of indium tin oxide (ITO) transparent plates sandwiching a vibrating diaphragm to create circular (30 mm radius) and annular (30 mm outer and 3 mm inner radius) push-pull electrostatic speakers. We then measured the displacement amplitudes and mode shapes produced by the devices. Vibration characteristics were used to predict sound pressure levels (SPLs) using the lumped parameter method (LPM) and distributed parameter method (DPM). The two measurement results obtained using a laser system were compared to the SPLs obtained using traditional acoustic measurement (AM) from 20 Hz to 20 kHz in order to verify our predictions. When using LPM and DPM, the SPL prediction results in the first three symmetric modes were in good agreement with the AM results. Under the assumption of linear operations, the DPM and amplitude-fluctuation electronic speckle pattern interferometry (ESPI) techniques proved effective in determining the visualization of mode shape (0,1)-(0,3). The use of ITO plates is a practical technique for the prediction of SPL, as well as measurement of mode shapes. The four evaluation methods, i.e. LPM, DPM, ESPI and AM, present a high degree of consistency with regard to vibrational mode and sound radiation characteristics.

Human Sound Externalization in Reverberant Environments

DEFF Research Database (Denmark)

Catic, Jasmina

In everyday environments, listeners perceive sound sources as externalized. In listening conditions where the spatial cues that are relevant for externalization are not represented correctly, such as when listening through headphones or hearing aids, a degraded perception of externalization may...... occur. In this thesis, the spatial cues that arise from a combined effect of filtering due to the head, torso, and pinna and the acoustic environment were analysed and the impact of such cues for the perception of externalization in different frequency regions was investigated. Distant sound sources...... were simulated via headphones using individualized binaural room impulse responses (BRIRs). An investigation of the influence of spectral content of a sound source on externalization showed that effective externalization cues are present across the entire frequency range. The fluctuation of interaural...

Radiation as a source of risk

International Nuclear Information System (INIS)

Katoh, Kazuaki

1999-01-01

Essence and nature of ionizing radiation as a source of risk are reviewed. Following to the appeal of necessity and importance of campaign for enlightening risk management, of individual and of society, background knowledge and information helpful to the promotion and discussion are summarized, also. (author)

National system of notification, authorization and inspection for the control of radiation sources in Ghana

International Nuclear Information System (INIS)

Schandorf, C.; Darko, E.O.; Yeboah, J.; Asiamah, S.D.

2001-01-01

The Radiation Protection Board (RPB) was established in 1993 in Ghana as the regulatory authority for radiation protection and safety of radiation sources; its functions are prescribed in the 1993 national radiation protection regulation. The report describes how the country's radiation protection and safety infrastructure have been established, including the RPB's organizational structure, with reference in particular to the main activities carried out by both the Regulatory Control Department and the Radiation and Waste Safety Department. It also briefly mentions the existing RPB human resources; the national system of notification, authorization and inspection of radiation sources; the inventory of radiation sources; and the management of disused radiation sources. Finally, the report identifies the two main problem areas regarding the regulatory control of radiation sources in the country. (author)

Experience with first aid in radiation sources accidents

International Nuclear Information System (INIS)

Klener, V.

1979-01-01

More than 20 years of experience at the Radiation Hygiene Centre of the Prague Institute of Hygiene and Epidemiology with prevention of accidents involving sources of radiation and the Centre's participation in providing medical aid in such accidents are described. A list is given of major types of accidents over the past decade. Prevalent were accidents involving sealed gamma sources, resulting in excessive local irradiation with serious skin damage or injury to some of the deeper structures of the hands, requiring plastic operation. Chromosomal picture investigation allows the estimation of the equivalent body dose which only reached higher values in a single case recorded (1.5 Gy = 150 rad). Organisational measures are described for emergencies and the task is shown by radiation hygiene departments attached to regional hygiene stations. The present system is capable of providing adequate, prompt and effective assistance. (author)

Control of sources of ionizing radiation in Lithuania

Energy Technology Data Exchange (ETDEWEB)

Mastauskas, Albinas; Ziliukas, Julius; Morkunas, Gendrutis [Radiation Protection Centre, Vilnius (Lithuania)

1997-12-31

Aspects connected with regulatory control of radioactive sources in Lithuania, such as keeping of the computer-based registry, investigation of arrested illegal radioactive material, decision making, control of users of radioactive sources are discussed. Most of the sources of ionizing radiation are smoke detectors and x-ray equipment. Potentially most dangerous sources (both sealed and unsealed) of therapy and industry are also presented 2 refs., 2 tabs.; e-mail: rsc at post.omnitel.net

UV radiation sources for artificial skin tanning and protection

International Nuclear Information System (INIS)

Zivkovic, D.; Hrnjak, M.

1999-01-01

UV radiation sources for artificial tanning are more utilized at the last time. UV radiation is not harmless, so there are not safety devices for tanning. If people do not want to avoid exposure to their radiation, than it is necessary to take the prevention measure: strictly dose of UV radiation according to skin type, use of appropriate protective eye-wears and respect for inhibit of some medicaments and some cosmetic products use. (author)

Fabrication of sealed radiation sources

International Nuclear Information System (INIS)

Mars, Jean.

1977-01-01

The description is given for fabricating a sealed radiation source, consisting in depositing on a metal substrate a thin active coat of a radioelement, termed first coat, submitting this coated substrate to an oxidation treatment in order to obtain on the first coat an inactive coat of an oxide of the metal, termed second coat, and depositing a coat of varnish on this second inactive coat [fr

Sound radiation quantities arising from a resilient circular radiator.

Science.gov (United States)

Aarts, Ronald M; Janssen, Augustus J E M

2009-10-01

Power series expansions in ka are derived for the pressure at the edge of a radiator, the reaction force on the radiator, and the total radiated power arising from a harmonically excited, resilient, flat, circular radiator of radius a in an infinite baffle. The velocity profiles on the radiator are either Stenzel functions (1-(sigma/a)2)n, with sigma the radial coordinate on the radiator, or linear combinations of Zernike functions Pn(2(sigma/a)2-1), with Pn the Legendre polynomial of degree n. Both sets of functions give rise, via King's integral for the pressure, to integrals for the quantities of interest involving the product of two Bessel functions. These integrals have a power series expansion and allow an expression in terms of Bessel functions of the first kind and Struve functions. Consequently, many of the results in [M. Greenspan, J. Acoust. Soc. Am. 65, 608-621 (1979)] are generalized and treated in a unified manner. A foreseen application is for loudspeakers. The relation between the radiated power in the near-field on one hand and in the far field on the other is highlighted.

Modeling and control of sound radiation by simply supported and cantilever beam coupled with smart material

Directory of Open Access Journals (Sweden)

Vitaly Makarenko

2007-03-01

Full Text Available  In this paper forced vibration of the beam due to bonded piezoelectric patch is considered. When an external excitation is applied to the beam, it starts to vibrate, and the resulting acoustic response is predicted from the analytical model, which is based on Bernoulli-Euler theory of beam vibration. Analytical research of the sound radiation by a finite elastic beam is done for criteria based on minimal total sound power level. Helmholtz equation and inhomogeneous differential equation for beam transverse motion defines the solution to this problem. Such solutions were found for boundary conditions of simply supported and cantilever beams. In order to solve the task two analytical methods were used for simply supported beam. The solutions received by Fourier transform and Green functions approach give the very similar results, thus, proving methods reliability. At the case studies the exerted voltage, phase, location and piezoelectric actuator length are varied in order to establish their influence on noise attenuation.

An investigation of the usability of sound recognition for source separation of packaging wastes in reverse vending machines.

Science.gov (United States)

Korucu, M Kemal; Kaplan, Özgür; Büyük, Osman; Güllü, M Kemal

2016-10-01

In this study, we investigate the usability of sound recognition for source separation of packaging wastes in reverse vending machines (RVMs). For this purpose, an experimental setup equipped with a sound recording mechanism was prepared. Packaging waste sounds generated by three physical impacts such as free falling, pneumatic hitting and hydraulic crushing were separately recorded using two different microphones. To classify the waste types and sizes based on sound features of the wastes, a support vector machine (SVM) and a hidden Markov model (HMM) based sound classification systems were developed. In the basic experimental setup in which only free falling impact type was considered, SVM and HMM systems provided 100% classification accuracy for both microphones. In the expanded experimental setup which includes all three impact types, material type classification accuracies were 96.5% for dynamic microphone and 97.7% for condenser microphone. When both the material type and the size of the wastes were classified, the accuracy was 88.6% for the microphones. The modeling studies indicated that hydraulic crushing impact type recordings were very noisy for an effective sound recognition application. In the detailed analysis of the recognition errors, it was observed that most of the errors occurred in the hitting impact type. According to the experimental results, it can be said that the proposed novel approach for the separation of packaging wastes could provide a high classification performance for RVMs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differential presence of anthropogenic compounds dissolved in the marine waters of Puget Sound, WA and Barkley Sound, BC.

Science.gov (United States)

Keil, Richard; Salemme, Keri; Forrest, Brittany; Neibauer, Jaqui; Logsdon, Miles

2011-11-01

Organic compounds were evaluated in March 2010 at 22 stations in Barkley Sound, Vancouver Island Canada and at 66 locations in Puget Sound. Of 37 compounds, 15 were xenobiotics, 8 were determined to have an anthropogenic imprint over natural sources, and 13 were presumed to be of natural or mixed origin. The three most frequently detected compounds were salicyclic acid, vanillin and thymol. The three most abundant compounds were diethylhexyl phthalate (DEHP), ethyl vanillin and benzaldehyde (∼600 n g L(-1) on average). Concentrations of xenobiotics were 10-100 times higher in Puget Sound relative to Barkley Sound. Three compound couplets are used to illustrate the influence of human activity on marine waters; vanillin and ethyl vanillin, salicylic acid and acetylsalicylic acid, and cinnamaldehyde and cinnamic acid. Ratios indicate that anthropogenic activities are the predominant source of these chemicals in Puget Sound. Published by Elsevier Ltd.

Fabrication of radiation sources for educational purposes from chemical fertilizers using compressing and forming method

International Nuclear Information System (INIS)

Kawano, Takao

2008-01-01

Chemical fertilizers contain potassium, which is composed of a small amount of naturally occurring potassium-40. The potassium-40 radionuclide emits beta and gamma radiation. Three brands of chemical fertilizer were used to fabricate disk-shaped radiation sources and the fabricated radiation sources were examined for applicability to an educational radiation course. In the examination, tests to determine dependence of count rate on distance, shielding thickness, and shielding materials were conducted using the radiation sources. Results showed that radiation sources fabricated from the three brands of chemical fertilizer were equivalent for explaining radiation characteristics, particularly those related to the dependence of radiation strength on distance and shielding thickness. The relation between shielding effect and mass density can be explained qualitatively. Thus, chemical fertilizer radiation sources can be a useful teaching aid for educational courses to better promote understanding of radiation characteristics and the principles of radiation protection. (author)

Localization of the gamma-radiation sources using the gamma-visor

Directory of Open Access Journals (Sweden)

Ivanov Kirill E.

2008-01-01

Full Text Available The search of the main gamma-radiation sources at the site of the temporary storage of solid radioactive wastes was carried out. The relative absorbed dose rates were measured for some of the gamma-sources before and after the rehabilitation procedures. The effectiveness of the rehabilitation procedures in the years 2006-2007 was evaluated qualitatively and quantitatively. The decrease of radiation background at the site of the temporary storage of the solid radioactive wastes after the rehabilitation procedures allowed localizing the new gamma-source.

Localization of the gamma-radiation sources using the gamma-visor

International Nuclear Information System (INIS)

Ivanov, K. E.; Ponomaryev-Stepnoi, N. N.; Stepennov, B. S.; Teterin, Y. A.; Teterin, A. Y.; Kharitonov, V. V.

2008-01-01

The search of the main gamma-radiation sources at the site of the temporary storage of solid radioactive wastes was carried out. The relative absorbed dose rates were measured for some of the gamma-sources before and after the rehabilitation procedures. The effectiveness of the rehabilitation procedures in the years 2006-2007 was evaluated qualitatively and quantitatively. The decrease of radiation background at the site of the temporary storage of the solid radioactive wastes after the rehabilitation procedures al lowed localizing the new gamma-source. (author)

Compact synchrotron radiation source

International Nuclear Information System (INIS)

Liu, N.; Wang, T.; Tian, J.; Lin, Y.; Chen, S.; He, W.; Hu, Y.; Li, Q.

1985-01-01

A compact 800 MeV synchrotron radiation source is discussed. The storage ring has a circumference of 30.3 m, two 90 degree and four 45 degree bending magnet sections, two long straight sections and four short straight sections. The radius of the bending magnet is 2.224m. The critical wave length is 24A. The injector is a 15 Mev Microtron Electrons are accelerated from 15 Mev to 800 Mev by ramping the field of the ring. The expected stored current will be around 100 ma

The effect of brain lesions on sound localization in complex acoustic environments.

Science.gov (United States)

Zündorf, Ida C; Karnath, Hans-Otto; Lewald, Jörg

2014-05-01

Localizing sound sources of interest in cluttered acoustic environments--as in the 'cocktail-party' situation--is one of the most demanding challenges to the human auditory system in everyday life. In this study, stroke patients' ability to localize acoustic targets in a single-source and in a multi-source setup in the free sound field were directly compared. Subsequent voxel-based lesion-behaviour mapping analyses were computed to uncover the brain areas associated with a deficit in localization in the presence of multiple distracter sound sources rather than localization of individually presented sound sources. Analyses revealed a fundamental role of the right planum temporale in this task. The results from the left hemisphere were less straightforward, but suggested an involvement of inferior frontal and pre- and postcentral areas. These areas appear to be particularly involved in the spectrotemporal analyses crucial for effective segregation of multiple sound streams from various locations, beyond the currently known network for localization of isolated sound sources in otherwise silent surroundings.

Light source for synchrotron radiation x-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL)

International Nuclear Information System (INIS)

Zhao Jiyong; Jiang Jianhua; Tian Yulian

1992-01-01

Characteristics of the synchrotron radiation source for X-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL) is described, local geometrical resolution of topographies is discussed, and the diffracting intensities of white beam topography is given

Analysis of polymer foil heaters as infrared radiation sources

International Nuclear Information System (INIS)

Witek, Krzysztof; Piotrowski, Tadeusz; Skwarek, Agata

2012-01-01

Infrared radiation as a heat source is used in many fields. In particular, the positive effect of far-infrared radiation on living organisms has been observed. This paper presents two technological solutions for infrared heater production using polymer-silver and polymer-carbon pastes screenprinted on foil substrates. The purpose of this work was the identification of polymer layers as a specific frequency range IR radiation sources. The characterization of the heaters was determined mainly by measurement of the surface temperature distribution using a thermovision camera and the spectral characteristics were determined using a special measuring system. Basic parameters obtained for both, polymer silver and polymer carbon heaters were similar and were as follows: power rating of 10–12 W/dm 2 , continuous working surface temperature of 80–90 °C, temperature coefficient of resistance (TCR) about +900 ppm/K for polymer-carbon heater and about +2000 ppm/K for polymer-silver, maximum radiation intensity in the wavelength range of 6–14 μm with top intensity at 8.5 μm and heating time about 20 min. For comparison purposes, commercial panel heater was tested. The results show that the characteristics of infrared polymer heaters are similar to the characteristics of the commercial heater, so they can be taken into consideration as the alternative infrared radiation sources.

Management of ionizing radiation sources in university, medical and industrial environments; Gestion des sources ionisantes en milieux universitaire, medical et industriel

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

This conference treats several subjects relative to the use of radioactive sources. The first session comprises three articles about ionizing sources and regulation. The second session, with three articles, tackles the question of radiation protection in the use of sources in industrial field. The third session, four articles, treats the same question but in the medicine and university media. The fourth session (three articles) is devoted to the organisation of radiation protection in the case of accidents. The fifth session concerns the management of spent sources (three articles). The sixth session studies the radiation protection of sources in Europe. The seventh and final session ends with the part and coordination of actors in radiation protection in the sources management (three articles). (N.C.)

Solar radiation data sources, applications, and network design

Energy Technology Data Exchange (ETDEWEB)

None

1978-04-01

A prerequisite to considering solar energy projects is to determine the requirements for information about solar radiation to apply to possible projects. This report offers techniques to help the reader specify requirements in terms of solar radiation data and information currently available, describes the past and present programs to record and present information to be used for most requirements, presents courses of action to help the user meet his needs for information, lists sources of solar radiation data and presents the problems, costs, benefits and responsibilities of programs to acquire additional solar radiation data. Extensive background information is provided about solar radiation data and its use. Specialized information about recording, collecting, processing, storing and disseminating solar radiation data is given. Several Appendices are included which provide reference material for special situations.

Trade and transport of radiation sources

International Nuclear Information System (INIS)

1996-01-01

The guide specifies the obligations pertaining to the trade in and transport of radiation sources and other matters to be taken into account in safety supervision. It also specifies obligations and procedures relating to transfrontier movements of radioactive waste contained in the EU Council Directive 92/3/Euratom. (7 refs.)

Experience with qualification examinations of workers handling ionizing radiation sources

International Nuclear Information System (INIS)

Skokanova, K.

1976-01-01

The organization is described of examinations which have to be passed by supervising staff and workers using radioactive ionizing radiation sources. The requirements are listed of the examination in which these workers have to prove their professional knowledge and skills. The said examinations significantly contribute to the establishment of a system of safeguards at workplaces using ionizing radiation sources and may help economize operations at these workplaces

Sound transmission reduction with intelligent panel systems

Science.gov (United States)

Fuller, Chris R.; Clark, Robert L.

1992-01-01

Experimental and theoretical investigations are performed of the use of intelligent panel systems to control the sound transmission and radiation. An intelligent structure is defined as a structural system with integrated actuators and sensors under the guidance of an adaptive, learning type controller. The system configuration is based on the Active Structural Acoustic Control (ASAC) concept where control inputs are applied directly to the structure to minimize an error quantity related to the radiated sound field. In this case multiple piezoelectric elements are employed as sensors. The importance of optimal shape and location is demonstrated to be of the same order of influence as increasing the number of channels of control.

Synchrotron radiation sources in the Soviet Union

International Nuclear Information System (INIS)

Kapitza, S.P.

1987-01-01

Synchrotron radiation (SR) is now recognized to be an important instrument for experimental work in many fields of science. Recently the application of SR in medicine and industry, especially as a light source for microelectronics production have been demonstrated. Thus the development of SR sources has now grown to become a significant and independent dimension for accelerator research and technology. This article describes SR work in the Soviet Union

Acoustic radiosity for computation of sound fields in diffuse environments

Science.gov (United States)

Muehleisen, Ralph T.; Beamer, C. Walter

2002-05-01

The use of image and ray tracing methods (and variations thereof) for the computation of sound fields in rooms is relatively well developed. In their regime of validity, both methods work well for prediction in rooms with small amounts of diffraction and mostly specular reflection at the walls. While extensions to the method to include diffuse reflections and diffraction have been made, they are limited at best. In the fields of illumination and computer graphics the ray tracing and image methods are joined by another method called luminous radiative transfer or radiosity. In radiosity, an energy balance between surfaces is computed assuming diffuse reflection at the reflective surfaces. Because the interaction between surfaces is constant, much of the computation required for sound field prediction with multiple or moving source and receiver positions can be reduced. In acoustics the radiosity method has had little attention because of the problems of diffraction and specular reflection. The utility of radiosity in acoustics and an approach to a useful development of the method for acoustics will be presented. The method looks especially useful for sound level prediction in industrial and office environments. [Work supported by NSF.

Assessment of occupational exposure due to external sources of radiation. Safety guide

International Nuclear Information System (INIS)

2000-01-01

Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments and nuclear fuel cycle facilities. Adequate radiation protection of workers is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy. The three Safety Guides on occupational radiation protection are jointly sponsored by the IAEA and the International Labour Office. The Agency gratefully acknowledges the contribution of the European Commission to the development of the present Safety Guide. The present Safety Guide addresses the assessment of exposure due to external sources of radiation in the workplace. Such exposure can result from a number of sources within a workplace, and the monitoring of workers and the workplace in such situations is an integral part of any occupational radiation protection programme. The assessment of exposure due to external radiation sources depends critically upon knowledge of the radiation type and energy and the conditions of exposure. The present Safety Guide reflects the major changes over the past decade in international practice in external dose assessment

Assessment of occupational exposure due to external sources of radiation. Safety guide

International Nuclear Information System (INIS)

2004-01-01

Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments and nuclear fuel cycle facilities. Adequate radiation protection of workers is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy. The three Safety Guides on occupational radiation protection are jointly sponsored by the IAEA and the International Labour Office. The Agency gratefully acknowledges the contribution of the European Commission to the development of the present Safety Guide. The present Safety Guide addresses the assessment of exposure due to external sources of radiation in the workplace. Such exposure can result from a number of sources within a workplace, and the monitoring of workers and the workplace in such situations is an integral part of any occupational radiation protection programme. The assessment of exposure due to external radiation sources depends critically upon knowledge of the radiation type and energy and the conditions of exposure. The present Safety Guide reflects the major changes over the past decade in international practice in external dose assessment

Assessment of occupational exposure due to external sources of radiation. Safety guide

International Nuclear Information System (INIS)

1999-01-01

Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments and nuclear fuel cycle facilities. Adequate radiation protection of workers is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy. The three Safety Guides on occupational radiation protection are jointly sponsored by the IAEA and the International Labour Office. The Agency gratefully acknowledges the contribution of the European Commission to the development of the present Safety Guide. The present Safety Guide addresses the assessment of exposure due to external sources of radiation in the workplace. Such exposure can result from a number of sources within a workplace, and the monitoring of workers and the workplace in such situations is an integral part of any occupational radiation protection programme. The assessment of exposure due to external radiation sources depends critically upon knowledge of the radiation type and energy and the conditions of exposure. The present Safety Guide reflects the major changes over the past decade in international practice in external dose assessment

Regulatory control and challenges in Medical facilities using ionising radiation sources

International Nuclear Information System (INIS)

Agarwal, S.P.

2008-01-01

Medical facilities utilising ionising radiation sources for diagnostic and treatment of cancer are regulated under the provisions of Atomic Energy (Radiation Protection) Rules, 2004 promulgated under the Atomic Energy Act 1962. The Competent Authority for the enforcement of the rules is Chairman, Atomic Energy Regulatory Board (AERB). Practice specific codes are issued by AERB for medical facilities such as Radiotherapy, Nuclear Medicine and Radiology. Regulatory process for control of medical facilities covers the entire life cycle of the radiation sources in three stages viz pre-Iicensing, during useful life and decommissioning and disposal. Pre-Iicensing requirements include use of type approved sources and equipment, approval of design layout of the facility and installation, exclusive (safe and secure) source storage facility when the equipment is not in use, radiation (area/individual) monitoring devices, qualified, trained and certified manpower, emergency response plans and commitment from the licensee for the safe disposal of disused/decayed sources. Compliance to these requirements makes the applicant eligible to obtain license from AERB for the operation of the medical facility. During the use of radiation sources, specific prior approval of the Competent Authority is required in respect of every source replacement, sale, transfer, transport, import and export. Further, all licensees are required to send the periodic safety Status reports to AERB as well as reporting of any off normal events. AERB conducts inspection of the facilities to ensure compliance with the safety requirements during operation of the facility. Violation of safety norms by licensee attracts enforcement action which includes suspension, modification or withdrawal of licensee for operation of the facility. Upon completion of the useful life of the source, the licensee decommissions the facility and returns the source to the original supplier. For returning the source, prior

Transition radiation in metal-metal multilayer nanostructures as a medical source of hard x-ray radiation

International Nuclear Information System (INIS)

Pokrovsky, A. L.; Kaplan, A. E.; Shkolnikov, P. L.

2006-01-01

We show that a periodic metal-metal multilayer nanostructure can serve as an efficient source of hard x-ray transition radiation. Our research effort is aimed at developing an x-ray source for medical applications, which is based on using low-energy relativistic electrons. The approach toward choosing radiator-spacer couples for the generation of hard x-ray resonant transition radiation by few-MeV electrons traversing solid multilayer structures for the energies of interest to medicine (30-50 keV) changes dramatically compared with that for soft x-ray radiation. We show that one of the main factors in achieving the required resonant line is the absence of the contrast of the refractive indices between the spacer and the radiator at the far wings of the radiation line; for that purpose, the optimal spacer, as a rule, should have a higher atomic number than the radiator. Having experimental goals in mind, we have considered also the unwanted effects due to bremsstrahlung radiation, absorption and scattering of radiated photons, detector-related issues, and inhibited coherence of transition radiation due to random deviation of spacing between the layers. Choosing as a model example a Mo-Ag radiator-spacer pair of materials, we demonstrate that the x-ray transition radiation line can be well resolved with the use of spatial and frequency filtering

Radiological protection, safety and security issues in the industrial and medical applications of radiation sources

International Nuclear Information System (INIS)

Vaz, Pedro

2015-01-01

The use of radiation sources, namely radioactive sealed or unsealed sources and particle accelerators and beams is ubiquitous in the industrial and medical applications of ionizing radiation. Besides radiological protection of the workers, members of the public and patients in routine situations, the use of radiation sources involves several aspects associated to the mitigation of radiological or nuclear accidents and associated emergency situations. On the other hand, during the last decade security issues became burning issues due to the potential malevolent uses of radioactive sources for the perpetration of terrorist acts using RDD (Radiological Dispersal Devices), RED (Radiation Exposure Devices) or IND (Improvised Nuclear Devices). A stringent set of international legally and non-legally binding instruments, regulations, conventions and treaties regulate nowadays the use of radioactive sources. In this paper, a review of the radiological protection issues associated to the use of radiation sources in the industrial and medical applications of ionizing radiation is performed. The associated radiation safety issues and the prevention and mitigation of incidents and accidents are discussed. A comprehensive discussion of the security issues associated to the global use of radiation sources for the aforementioned applications and the inherent radiation detection requirements will be presented. Scientific, technical, legal, ethical, socio-economic issues are put forward and discussed. - Highlights: • The hazards associated to the use of radioactive sources must be taken into account. • Security issues are of paramount importance in the use of radioactive sources. • Radiation sources can be used to perpetrate terrorist acts (RDDs, INDs, REDs). • DSRS and orphan sources trigger radiological protection, safety and security concerns. • Regulatory control, from cradle to grave, of radioactive sources is mandatory.

Synchrotron radiation as a source for quantitative XPS: advantages and consequences

International Nuclear Information System (INIS)

Rosseel, T.M.; Carlson, T.A.; Negri, R.E.; Beall, C.E.; Taylor, J.W.

1986-01-01

Synchrotron radiation (SR) has a variety of properties which make it an attractive source for quantitative x-ray photoelectron spectroscopy (XPS). Among the most significant are high intensity and tunability. In addition, the intensity of the dispersed radiation is comparable to laboratory line sources. Synchrotron radiation is also a clean source, i.e., it will not contaminate the sample, because it operates under ultra-high vacuum conditions. We have used these properties to demonstrate the advantages of SR as a source for quantitative XPS. We have also found several consequences associated with this source which can either limit its use or provide unique opportunities for analysis and research. Using the tunability of SR, we have measured the energy dependence of the 3p photoionization cross sections of Ti, Cr, and Mn from 50 to 150 eV above threshold at the University of Wisconsin's Tantalus electron-storage ring

Waveform analysis of sound

CERN Document Server

Tohyama, Mikio

2015-01-01

What is this sound? What does that sound indicate? These are two questions frequently heard in daily conversation. Sound results from the vibrations of elastic media and in daily life provides informative signals of events happening in the surrounding environment. In interpreting auditory sensations, the human ear seems particularly good at extracting the signal signatures from sound waves. Although exploring auditory processing schemes may be beyond our capabilities, source signature analysis is a very attractive area in which signal-processing schemes can be developed using mathematical expressions. This book is inspired by such processing schemes and is oriented to signature analysis of waveforms. Most of the examples in the book are taken from data of sound and vibrations; however, the methods and theories are mostly formulated using mathematical expressions rather than by acoustical interpretation. This book might therefore be attractive and informative for scientists, engineers, researchers, and graduat...

Lexical and perceptual grounding of a sound ontology

NARCIS (Netherlands)

Lobanova, Anna; Spenader, Jennifer; Valkenier, Bea; Matousek,; Mautner, P

2007-01-01

Sound ontologies need to incorporate source unidentifiable sounds in an adequate and consistent manner. Computational lexical resources like WordNet have either inserted these descriptions into conceptual categories, or make no attempt to organize the terms for these sounds. This work attempts to

Physics of thermo-acoustic sound generation

Science.gov (United States)

Daschewski, M.; Boehm, R.; Prager, J.; Kreutzbruck, M.; Harrer, A.

2013-09-01

We present a generalized analytical model of thermo-acoustic sound generation based on the analysis of thermally induced energy density fluctuations and their propagation into the adjacent matter. The model provides exact analytical prediction of the sound pressure generated in fluids and solids; consequently, it can be applied to arbitrary thermal power sources such as thermophones, plasma firings, laser beams, and chemical reactions. Unlike existing approaches, our description also includes acoustic near-field effects and sound-field attenuation. Analytical results are compared with measurements of sound pressures generated by thermo-acoustic transducers in air for frequencies up to 1 MHz. The tested transducers consist of titanium and indium tin oxide coatings on quartz glass and polycarbonate substrates. The model reveals that thermo-acoustic efficiency increases linearly with the supplied thermal power and quadratically with thermal excitation frequency. Comparison of the efficiency of our thermo-acoustic transducers with those of piezoelectric-based airborne ultrasound transducers using impulse excitation showed comparable sound pressure values. The present results show that thermo-acoustic transducers can be applied as broadband, non-resonant, high-performance ultrasound sources.

Source of broadband Jovian Kilometric radiation

Energy Technology Data Exchange (ETDEWEB)

Jones, D.; Leblanc, Y.

1987-02-01

Broadband Jovian Kilometric radiation was observed by Voyagers 1 and 2 to be beamed away from the zenomagnetic equatorial plane. Two theories were proposed for the equatorial shadow zone. One suggested that Io plasma torus forms an obstacle to radiation produced on auroral field lines. The other theory proposed that the source is located on the outer flanks of the torus, the beaming being inherent to the emission mechanism. Results are presented which indicate that the latter is consistent with the observations and it would appear that the emission is produced by linear mode conversion of electrostatic upper hybrid to electromagnetic waves in plasma density gradients.

Source of broadband Jovian Kilometric radiation

International Nuclear Information System (INIS)

Jones, D.; Leblanc, Y.

1987-01-01

Broadband Jovian Kilometric radiation was observed by Voyagers 1 and 2 to be beamed away from the zenomagnetic equatorial plane. Two theories were proposed for the equatorial shadow zone. One suggested that Io plasma torus forms an obstacle to radiation produced on auroral field lines. The other theory proposed that the source is located on the outer flanks of the torus, the beaming being inherent to the emission mechanism. Results are presented which indicate that the latter is consistent with the observations and it would appear that the emission is produced by linear mode conversion of electrostatic upper hybrid to electromagnetic waves in plasma density gradients

A century's challenges. Historical overview of radiation sources in the USA

International Nuclear Information System (INIS)

Lubenau, J.O.

1999-01-01

A historical overview of radiation sources in the USA, including lost or abandoned ones is given in this paper. The important lesson to be learned from operational experience with radiation sources is that periodic contacts by regulators with the users serve as reminders to them of the need to maintain control and countability of the sources, to properly dispose the sources when not needed, and to provide for their safe application. The historical perspective induces another lesson, when dealing with radiological protection issues, the knowledge learned from the past experience should not be ignored

Determining the temperature and density distribution from a Z-pinch radiation source

International Nuclear Information System (INIS)

Matuska, W.; Lee, H.

1997-01-01

High temperature radiation sources exceeding one hundred eV can be produced via z-pinches using currently available pulsed power. The usual approach to compare the z-pinch simulation and experimental data is to convert the radiation output at the source, whose temperature and density distributions are computed from the 2-D MHD code, into simulated data such as a spectrometer reading. This conversion process involves a radiation transfer calculation through the axially symmetric source, assuming local thermodynamic equilibrium (LTE), and folding the radiation that reaches the detector with the frequency-dependent response function. In this paper the authors propose a different approach by which they can determine the temperature and density distributions of the radiation source directly from the spatially resolved spectral data. This unfolding process is reliable and unambiguous for the ideal case where LTE holds and the source is axially symmetric. In reality, imperfect LTE and axial symmetry will introduce inaccuracies into the unfolded distributions. The authors use a parameter optimization routine to find the temperature and density distributions that best fit the data. They know from their past experience that the radiation source resulting from the implosion of a thin foil does not exhibit good axial symmetry. However, recent experiments carried out at Sandia National Laboratory using multiple wire arrays were very promising to achieve reasonably good symmetry. For these experiments the method will provide a valuable diagnostic tool

Standard light source utilizing spontaneous radiation

International Nuclear Information System (INIS)

Yamamoto, O.; Takenaga, M.; Tsujimoto, Y.

1975-01-01

A standard light source is described utilizing spontaneous radiation made by mixing a fluorescent substance LnVO 4 :X (wherein Ln is Y or Gd, and X is Dy or Eu) with a radioactive substance containing a radioactive isotope which is less in the degree of temperature variation of the intensity of emitted light and excellent in stability. Particularly when used in a light-receiving device having photomultiplier tubes, the said light source emits light quite similar to that of a thermoluminescent substance such as CaSO 4 :X (wherein X is Im, Dy, Sm or Mn), LiF or Mg 2 SiO 4 :Tb, and is excellent as a calibration high-stability standard light source for use in the above-mentioned light-receiving device. (auth)

Systems analysis and engineering of the X-1 Advanced Radiation Source

International Nuclear Information System (INIS)

Rochau, G.E.; Hands, J.A.; Raglin, P.S.; Ramirez, J.J.

1998-01-01

The X-1 Advanced Radiation Source, which will produce ∼ 16 MJ in x-rays, represents the next step in providing US Department of Energy's Stockpile Stewardship program with the high-energy, large volume, laboratory x-ray sources needed for the Radiation Effects Science and Simulation (RES), Inertial Confinement Fusion (ICF), and Weapon Physics (WP) Programs. Advances in fast pulsed power technology and in z-pinch hohlraums on Sandia National Laboratories' Z Accelerator in 1997 provide sufficient basis for pursuing the development of X-1. This paper will introduce the X-1 Advanced Radiation Source Facility Project, describe the systems analysis and engineering approach being used, and identify critical technology areas being researched

Development of quality assurance procedures for production of sealed radiation source

CERN Document Server

Nam, J H; Cho, W K; Han, H S; Hong, S B; Kim, K H; Kim, S D; Lee, Y G; Lim, N J

2001-01-01

The quality assurance procedures for sealed radiation sources production using HANARO and RIPF have been developed. The detailed quality assurance procedures are essential to manage the whole work process effectively and ensure the quality of the produced sealed sources. Through applying this quality assurance procedures to the entire production works of the sealed radiation sources, it is expected that the quality of the products, the safety of the works and the satisfaction of the customers will be increased.

Design and Construction of a Radiation Source of Extreme Flux

OpenAIRE

Valle Brozas, Francisco

2017-01-01

[EN]The present thesis consists of the design and construction of an X-ray source through the interaction of an ultra-intense laser with a solid and/or liquid target. Specifically, the laser technology suitable for this purpose has been investigated, the characteristics of the laser-matter interaction have been studied and possible applications of the generated X-radiation (and accelerated electrons) have been explored. Nowadays, the development of sources of ionizing radiation through la...

Rendering harmless and deposition of spent sealed radiation sources

International Nuclear Information System (INIS)

Cholerzynski, A.

1999-01-01

The sealed radiation sources are commonly used in medicine, agriculture, industry and scientific research. There is millions of such sources being used all over the world. The purpose of this article is to present a modes of management and disposal of spent sealed radioactive sources in different countries as well as methods being recommended in Poland

Radiological protection, safety and security issues in the industrial and medical applications of radiation sources

Science.gov (United States)

Vaz, Pedro

2015-11-01

The use of radiation sources, namely radioactive sealed or unsealed sources and particle accelerators and beams is ubiquitous in the industrial and medical applications of ionizing radiation. Besides radiological protection of the workers, members of the public and patients in routine situations, the use of radiation sources involves several aspects associated to the mitigation of radiological or nuclear accidents and associated emergency situations. On the other hand, during the last decade security issues became burning issues due to the potential malevolent uses of radioactive sources for the perpetration of terrorist acts using RDD (Radiological Dispersal Devices), RED (Radiation Exposure Devices) or IND (Improvised Nuclear Devices). A stringent set of international legally and non-legally binding instruments, regulations, conventions and treaties regulate nowadays the use of radioactive sources. In this paper, a review of the radiological protection issues associated to the use of radiation sources in the industrial and medical applications of ionizing radiation is performed. The associated radiation safety issues and the prevention and mitigation of incidents and accidents are discussed. A comprehensive discussion of the security issues associated to the global use of radiation sources for the aforementioned applications and the inherent radiation detection requirements will be presented. Scientific, technical, legal, ethical, socio-economic issues are put forward and discussed.

Sound response of superheated drop bubble detectors to neutrons

International Nuclear Information System (INIS)

Gao Size; Chen Zhe; Liu Chao; Ni Bangfa; Zhang Guiying; Zhao Changfa; Xiao Caijin; Liu Cunxiong; Nie Peng; Guan Yongjing

2012-01-01

The sound response of the bubble detectors to neutrons by using 252 Cf neutron source was described. Sound signals were filtered by sound card and PC. The short-time signal energy. FFT spectrum, power spectrum, and decay time constant were got to determine the authenticity of sound signal for bubbles. (authors)

Radiation safety aspects of the LINAC coherent light source

International Nuclear Information System (INIS)

Vylet, V.; Fasso, A.; Rokni, S.H.

1998-01-01

The radiation protection systems, which comprise the Personnel Protection System (PPS), Beam Containment System (BCS), and shielding, are described. The radiation sources and methods of their assessment are highlighted; these include bremsstrahlung and neutrons from electron beam losses, gas bremsstrahlung, synchrotron radiation, muons, and induced activity. By way of example, a plot of tissue dose as a function of distance from beam axis at the end of the experimental hutch is reproduced. (P.A.)

Visualizing Sound Directivity via Smartphone Sensors

OpenAIRE

Hawley, Scott H.; McClain Jr, Robert E.

2017-01-01

We present a fast, simple method for automated data acquisition and visualization of sound directivity, made convenient and accessible via a smartphone app, "Polar Pattern Plotter." The app synchronizes measurements of sound volume with the phone's angular orientation obtained from either compass, gyroscope or accelerometer sensors and produces a graph and exportable data file. It is generalizable to various sound sources and receivers via the use of an input-jack-adaptor to supplant the smar...

Safety issues in the handling of radiation sources in category IV gamma radiation facilities

International Nuclear Information System (INIS)

Kohli, A.K.

2002-01-01

There is potential for incidents/accidents related to handling of radiation sources. This is increasing due to the fact that more number of plants that too with much larger levels of activity are now coming up. Such facilities produce very high levels of exposure rates during irradiation. A person accidentally present in the irradiation cell can receive a lethal dose within a very short time. Apart from safety requirements during operation and maintenance of these facilities, safety during loading and unloading of sources is important. Category IV type irradiators are the most common. Doubly encapsulated Co-60 slugs are employed to form the source pencils. These irradiators employ a water pool for safely storing the source pencils when irradiation of the products is not going on or when human access is needed into the irradiation cell for some maintenance or source loading/unloading operations. Safety during loading/unloading operations of source pencils is important. In design itself care needs to be taken such that all such operations are convenient and any incident will not lead to a situation where it becomes difficult to come out. Different situations, which can arise during handling of radiation sources and suggested designs to obviate such tight situations, are discussed. (Author)

Effects of Active and Passive Hearing Protection Devices on Sound Source Localization, Speech Recognition, and Tone Detection.

Directory of Open Access Journals (Sweden)

Andrew D Brown

Full Text Available Hearing protection devices (HPDs such as earplugs offer to mitigate noise exposure and reduce the incidence of hearing loss among persons frequently exposed to intense sound. However, distortions of spatial acoustic information and reduced audibility of low-intensity sounds caused by many existing HPDs can make their use untenable in high-risk (e.g., military or law enforcement environments where auditory situational awareness is imperative. Here we assessed (1 sound source localization accuracy using a head-turning paradigm, (2 speech-in-noise recognition using a modified version of the QuickSIN test, and (3 tone detection thresholds using a two-alternative forced-choice task. Subjects were 10 young normal-hearing males. Four different HPDs were tested (two active, two passive, including two new and previously untested devices. Relative to unoccluded (control performance, all tested HPDs significantly degraded performance across tasks, although one active HPD slightly improved high-frequency tone detection thresholds and did not degrade speech recognition. Behavioral data were examined with respect to head-related transfer functions measured using a binaural manikin with and without tested HPDs in place. Data reinforce previous reports that HPDs significantly compromise a variety of auditory perceptual facilities, particularly sound localization due to distortions of high-frequency spectral cues that are important for the avoidance of front-back confusions.

Brilliant radiation sources by laser-plasma accelerators and optical undulators

Energy Technology Data Exchange (ETDEWEB)

Debus, Alexander

2012-09-06

This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

Brilliant radiation sources by laser-plasma accelerators and optical undulators

International Nuclear Information System (INIS)

Debus, Alexander

2012-01-01

This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

The present problems of hygienic supervising of workplaces with ionizing radiation sources

International Nuclear Information System (INIS)

Husar, J.

1995-01-01

This paper deals with the problems of hygienic supervising of workplaces with ionizing radiation sources in Bratislava. Most problems consist in present economic transformation of State Corporations. Abolishing of previous State Corporations and arising of new organizations means new field of their activities. It often happens, that previously used ionizing radiation sources, X-ray tubes, or radioactive sources, are not longer to use and it is necessary to remove corresponding workplaces.The big State Corporation with series of subsidiaries in whole Slovakia was divided to many new smaller Joint-stock Corporations. A subsidiary possessed workplace with X-ray tube and sealed radioactive source of medium radioactivity. During a routine hygienic inspection was found, that the original establishment was abolished, all personal dismissed and another organization is going to move at this place. New organization personnel has not known,that the previous workplace was such one with radiation sources. The situation was complicated by the fact, that new management had no connection to previous personnel and had not sufficient information about abolished establishment. The problem of supervising workplaces with ionizing radiation sources is described. (J.K.)

The present problems of hygienic supervising of workplaces with ionizing radiation sources

Energy Technology Data Exchange (ETDEWEB)

Husar, J [State Health Institute of Slovak Republic, Bratislava (Czech Republic)

1996-12-31

This paper deals with the problems of hygienic supervising of workplaces with ionizing radiation sources in Bratislava. Most problems consist in present economic transformation of State Corporations. Abolishing of previous State Corporations and arising of new organizations means new field of their activities. It often happens, that previously used ionizing radiation sources, X-ray tubes, or radioactive sources, are not longer to use and it is necessary to remove corresponding workplaces.The big State Corporation with series of subsidiaries in whole Slovakia was divided to many new smaller Joint-stock Corporations. A subsidiary possessed workplace with X-ray tube and sealed radioactive source of medium radioactivity. During a routine hygienic inspection was found, that the original establishment was abolished, all personal dismissed and another organization is going to move at this place. New organization personnel has not known,that the previous workplace was such one with radiation sources. The situation was complicated by the fact, that new management had no connection to previous personnel and had not sufficient information about abolished establishment. The problem of supervising workplaces with ionizing radiation sources is described. (J.K.).

MCNP model for the many KE-Basin radiation sources

International Nuclear Information System (INIS)

Rittmann, P.D.

1997-01-01

This document presents a model for the location and strength of radiation sources in the accessible areas of KE-Basin which agrees well with data taken on a regular grid in September of 1996. This modelling work was requested to support dose rate reduction efforts in KE-Basin. Anticipated fuel removal activities require lower dose rates to minimize annual dose to workers. With this model, the effects of component cleanup or removal can be estimated in advance to evaluate their effectiveness. In addition, the sources contributing most to the radiation fields in a given location can be identified and dealt with

Active control of turbulent boundary layer sound transmission into a vehicle interior